The influence of Late Ordovician volcanism on the marine environment based on high-resolution mercury data from South China

Abstract Volcanic ash interbeds in the Late Ordovician strata South China record highfrequency volcanic activity. To assess impact of these events on climate and marine biological evolutionary crisis during Mass Extinction (LOME), we present high-resolution measurements mercury (Hg) concentrations organic carbon isotope ratios (δ13Corg) an Ordovician–Silurian sedimentary succession (Muchanggou section). The results show that high-frequency layers Hg enrichments developed synchronously Katian graptolite P. pacificus (Lower Subzone) T. typicus biozones are coupled with a negative shift ~1‰ δ13Corg, which reflects perturbation surface cycles by intense Based fluxes, it is estimated more than 1.1 × 1013 tons CO2 were emitted activities China, interrupted growth polar ice sheet rapid cooling tropical oceans mid-Boda event. As volcanism weakened, increased weathering led to Hirnantian. Both regional global biodiversity declined rapidly end volcanism, suggests ecological was related series disruptions biogeochemical post-volcanic period.