... The cause of the end-Guadalupian extinction event is still unclear, but most scholars believe that the biotic crisis can be attributed to the eruption of the Emeishan large igneous province (Courtillot et al., 1999;Wang and Sugiyama, 2000;Ali et al., 2002;Zhou et al., 2002;Lai et al., 2008;Bond and Wignall, 2009;Wignall et al., 2009a;Xu et al., 2010;Shellnutt, 2014;Zhong et al., 2014;Zhao et al., 2016;Huang et al., 2019a;Liu et al., 2021), global climate change (Isozaki et al., 2007;Cheng et al., 2019;Wang et al., 2020), sea-level fall (Haq and Schutter, 2008;Wignall et al., 2009b;Qiu et al., 2014;Arefi-fard, 2018;, and ocean anoxia Wei et al., 2016;Saitoh et al., 2017), which have also been suggested as possible causes of the mass extinction. In addition, the 13 C and 87 Sr/ 86 Sr isotope ratios in late Guadalupian seawater fluctuated dramatically due to various geologic events, with 13 C values decreasing by 2%-8% near the Guadalupian-Lopingian boundary (Veizer et al., 1999;Chen et al., 2011a;Shen et al., 2013;Jost et al., 2014;Shi et al., 2017;Wei et al., 2018;Bagherpour et al., 2020;Zhu et al., 2021), and 87 Sr/ 86 Sr ratios decreased to their lowest values since the Phanerozoic in the Capitanian (Veizer et al., 1999;McArthur et al., 2001;Korte et al., 2003Korte et al., , 2006Kani et al., 2013;Isozaki and Servais, 2018;Huang et al., 2019a;Kani and Isozaki, 2021;Wang et al., 2021). Further study of the paleoceanographic significance of the late Guadalupian could considerably enhance our understanding of the end-Guadalupian biotic crisis and the series of global geologic events that occurred during this period. ...