A transient peak in marine sulfate after the 635-Ma snowball Earth
Yongbo Peng, Huiming Bao, Ganqing Jiang, Peter W. Crockford, Dong Feng, Shuhai Xiao, Alan J. Kaufman, Jiasheng Wang
Abstract
Significance Earth system’s response to major perturbations is of paramount interest. On the basis of multiple isotope compositions for pyrite, carbonate-associated sulfate, carbonates, and organics within, we inferred that the much-debated, enigmatic, extremely 13 C-depleted calcite cements in the ∼635-Ma cap carbonates in South China preserve geochemical evidence for marine microbial sulfate reduction coupled to anaerobic oxidation of methane. This interpretation implies the existence of a brief interval of modern-level marine sulfate. We determined that this interval coincides with the earliest Ediacaran 17 O-depletion episode, and both likely occurred within ∼50 ky since the onset of the 635-Ma meltdown, revealing an astonishing pace of transformation of the Earth system in the aftermath of Earth’s latest snowball glaciation.