Quantitative Characterization and Sedimentary Model of Mixed Deposits in the Middle–Lower Ordovician along the Southeastern Margin of the Upper Yangtze Region.

On the basis of field outcrop observation and preliminary lithofacies identification, combined with indoor rock thin section identification, this article uses cluster analysis method to identify and divide the carbonate rock siliceous clastic rock facies in the mixed sedimentary system of the study area. During the research process, continuous systematic sampling was conducted on the Hailong section and the Yanhe section.

During the sampling process, only fresh rock samples were collected, avoiding areas with severe weathering and significant late diagenesis. On the basis of thin section identification statistics, particle components, matrix, and cement with paleoenvironmental indicative significance are selected as clustering variables, and different lithofacies are classified and identified through clustering analysis. This method has good objectivity and recognition efficiency, and can effectively improve the accuracy of lithofacies classification.