中国科学院南京地质古生物研究所机构知识库

The spread of marine anoxia is believed to have played a key role in the development of the SPICE (Steptoean Positive Carbon Isotope Excursion) event and the end-Marjuman extinction in the late Cambrian (similar to 497.5 m.y. ago), but their cause-and-effect relationship is poorly constrained. Here we present an integrated analysis of carbonate delta 13C, cerium anomalies (Ce/Ce*), and genus-level diversity data of trilobites from the North China Platform. Our results show tightly coupled changes between the SPICE, an increase in Ce/Ce*, and a trilobite turnover event, which we interpret as indicating enhanced productivity and organic remineralization, leading to the development of low-oxygen conditions in shallowwater settings. This study therefore establishes a direct link between local ecological stress and trilobite turnover during the global SPICE event. Furthermore, the presence of low-oxygen rather than fully anoxic conditions during the peak of the SPICE event could explain the nature of the end-Marjuman crisis, which was characterized by the replacement of shallowwater fauna by deeper-water counterparts that were potentially more tolerant of hypoxia.