Middle Jurassic Carbon Isotope Stratigraphy of Shallow-Water Carbonate Deposits from the Qiangtang Basin, China

Shallow carbonate deposits represent highly sensitive ecological systems and can provide valuable information for understanding the climate system and sea-level changes in the geological past. However, decoding these archives can be challenging due to the low stratigraphic resolution achieved through biostratigraphy. This is particularly the case for the Middle Jurassic carbonate deposits of the Qiangtang Basin in Tibet, where the lack of typical index fossils hinders precise correlations between different sections, compounded by challenging outcrop accessibility. Carbon isotope (δ¹³C) stratigraphy has been applied as a reliable tool for comparing and calibrating biostratigraphic schemes on both local and global scales. In this study, high-resolution δ¹³C analyses of bulk carbonate from the studied section are investigated, and a δ¹³C chemostratigraphic correlation panel is presented for the Buqu Formation. The chemostratigraphic data presented here enable the confirmation and refinement of pre-existing biostratigraphic data and the establishment of a composite high-resolution stratigraphic framework, enhancing correlation with the western Tethys carbon isotope record. Overall, this framework also allows a better understanding of the impact of carbon cycle disturbances on Middle Jurassic shallow-marine carbonate systems.