1. Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China;

2. College of Earth and Planetary Sciences, Chengdu University of Technology, Chengdu 610059, China

The Tangjiashan lead-zinc deposit, located on the southwestern margin of the Sichuan Basin, is rich in bitumen, and the lead-zinc ore and bitumen coexist closely, indicating a close genetic relationship between lead-zinc mineralization and hydrocarbon reservoir formation. However, whether bitumen shares the same source as the current gas reservoirs within the basin or other destroyed gas reservoirs along the basin margins remains unknown. Here, we conducted an organic geochemical analysis of bitumen in this deposit and identified the sources of hydrocarbons by comparing biomarker compounds with those of potential source rocks. The authors found that the bitumen in the Tangjiashan lead-zinc deposit has good comparability with the hydrocarbon source rocks of the Cambrian Qiongzhusi Formation, suggesting that the primary sources of oil in this ancient hydrocarbon reservoir are muddy source rocks of the Qiongzhusi Formation. This research is important for enhancing the understanding of the genetic connection between lead-zinc mineralization and hydrocarbon formation, providing crucial insights for strategies to explore both metal ores and hydrocarbons and advancing the geological understanding of petroleum systems in the Sichuan Basin.?