Anomalously high enrichment of mercury in early Cambrian black shales in South China

The widespread lower Cambrian black shales reflect a significant anoxic event during a global transgression, recording synergistic changes in the marine environment and biological evolution. Extremely high Hg (714–6187 ppb, average is 3380 ppb) contents and Hg to total organic carbon ratios (Hg/TOC: 120–765 ppb/wt.%) were observed in the Danquan section of South China, suggesting that extensive volcanic activities may occur during the early...