中国科学院南京地质古生物研究所机构知识库

Neoproterozoic glaciations have drawn worldwide attention in recent years because of their influence on atmosphere, hydrosphere, biosphere, lithosphere, and potential causal relationship to the subsequent Cambrian evolutionary explosion which represents the most important event in the history of life on Earth. The Snowball Earth hypothesis predicts a rapid and synchronous initiation of the Neoproterozoic glaciations, but convincing radiometric dates to constrain this hypothesis are yet to be established. Dating this event is often compromised by indistinct stratigraphic relationships and the presence of detrital zircon grains. In this study, we present a chemical abrasion-isotope dilution-isotope ratio mass spectrometry (CA-ID-IRMS) U-Pb zircon age from the upper Gongdong Formation of South China, ca. 25 m below the base of the Chang'an diamictite. This new data combined with Monte Carlo modelling suggests the onset of the Sturtian glaciation, in South China, occurred after < 718.8 Ma, possibly 717.61 +/- 1.65 Ma. This new age is consistent with the geochronological records in Laurentia and the Arabian-Nubian Shield, an important step forward for testing rapid and synchronous global Sturtian glaciation.