Objective: The fine-grained carbonate rocks with typical characteristics and well-preserved laminations occurred at the third member of the Lower Triassic Jialingjiang Formation, Nanzhang-Yuan 'an area. This study aims to summarize the characteristics of fine-grained carbonate laminates, and elucidate the formation mechanisms and the depositional environments of the fine-grained carbonate laminates. Methods: In this study, field observation in combination with petrographic analysis under normal light, fluorescent, and scanning electronic microscopes, as well as geochemical analysis (LA-ICP-MS mapping) were conducted to solve these problems. Results: The laminae are composed of an alternating stacking of dark laminae and light laminae, with an average thickness ranging from 0.22 ~ 0.62 mm. There are abundant organic matter, extracellular polymeric substance (EPS), and framboidal pyrites as well as clay minerals preserved within the dark laminae, while light laminae are rich in calcite crystals with a few dolomitic crystals but rare clay minerals. LA-ICP-MS mapping analysis indicates different contents of some major elements within different laminae. Conclusions: The study elucidates the formation mechanisms and depositional environments of the fine-grained carbonate laminates. The formation of the dark laminae is attributed to organic matter and clay mineral adsorption, biomineralization and organomineralization of microbial organisms. While the light laminae may precipitate in a supersaturated calcium carbonate environment. These all indicate that those fine-grained carbonate laminates were deposited in a stagnant, reduced, hypersaline tidal flat pond environment.