Abstract: The Late Ordovician is a crucial period in geological history, during which deposited carbonates recorded the changes of the earth’s environment, providing a foundation for studies of the extinction events at the end of Ordovician. In this research, we collected polarized microscope images of the Late Ordovician carbonate rock thin sections and, on the basis of that, identified the fossil fragment contents. The research had a geographical scope of Kelpin in northwestern Tarim and Yichang in South China and covered a stratigraphic range from the Sandbian to the Katian, with sampling intervals of 0.5–2 m in the Tarim and 0.2–0.3 m in South China, respectively. The dataset can be used in comparative analyses when used in combination with those from other regions, which would add to subsequent studies on the paleoceanography and paleoenvironments of the Ordovician, and provide data support for building the spatial variation model of carbonate rocks deposited during the late Ordovician.
Keywords: Upper Ordovician; Northwest Tarim; middle Yangtze region; carbonate; fossil fragment