Resolving the stratigraphic problem of the Ediacaran–Cambrian (E–C) transition in deep-water slope settings is not only crucial for investigating the emergence of early ecosystem but also beneficial for the petroleum exploration associated with the Early Paleozoic source rocks. Although the lower Cambrian strata in the Deyang-Anyue trough of the Sichuan Basin have recently become a focus of natural gas exploration, the stratigraphy of the lower Cambrian deep-water settings in the northern end of the trough remains poorly constrained, due to the lack of biostratigraphic and chemostratigraphic evidence. This research provides a comprehensive stratigraphic analysis of the Cambrian Qiujiahe Formation and the underlying Shuijing Formation at the Qiujiahe Section, Chenjia Village, Guangyuan City, integrating evidence from lithostratigraphy, microfacies analysis, high-resolution carbonate carbon (δ13Ccarb) and organic carbon (δ13Corg) chemostratigraphy, and microfossil biostratigraphy. The δ13Ccarb data exhibit a negative excursion in the upper part of the Shuijing Formation, which can be correlated with the Ediacaran DOUNCE/Shuram excursion, while signals possibly correlative with the Basal Cambrian Carbon Isotope Excursion (BACE) are recovered near the top of this formation. The δ13Corg profile in the Qiujiahe Formation is also correlated with those reported from other lower Cambrian slope deposits in South China. Critically, we report a diverse early Cambrian chert-hosted microfossil assemblage from the Qiujiahe Formation, consisting of mineralized skeletal and carbonaceous filmy fossils. This assemblage corresponds to the recently established Terreneuvian microfossil assemblage, which is broadly distributed in the southern part of the Yangtze Block but now first found on the northwestern margin. The integration of these datasets establishes the E–C boundary during the Shuijing-Qiujiahe transition. The non-silicified black shale starting with a nodule-containing level in the upper Qiujiahe Formation could be correlated with the Cambrian Stage 3. This study demonstrates the usefulness of the microfossil assemblage in the stratigraphic correlation of the Terreneuvian cherts. The integrated bio- and δ13Corg chemostratigraphic methods seem to be a practical tool for the stratigraphic studies of the often chertified slope successions in the lower Cambrian of South China.
