Termination of Sturtian glaciation with protracted, multiple volcanic eruptions

The Sturtian glaciation of the Cryogenian represents a unique, global, protracted icehouse climatic event in Earth's history. The Snowball Earth hypothesis predicts that the termination of the Sturtian glaciation was globally synchronous and rapid. Long-term, volcanic degassing has been suggested to trigger the end of the Sturtian glaciation, but whether intense volcanism bracketing the termination of the glaciation on several cratons played a pivotal role in ending the glaciation has not yet been resolved. Here, we report a high-precision, U-Pb zircon, chemical-abrasion, isotope-dilution, thermal-ionization mass-spectrometry date of 661.86 ± 1.06 Ma for a tuff layer of the basal Datangpo Formation in South China, which is a manganese-rich, carbonaceous shale sequence deposited during deglaciation in the aftermath of the Sturtian glaciation. This volcanic age is consistent with a previously published date of 660.98 ± 0.31 Ma for the Datangpo Formation, but statistically different within analytical uncertainties from the date of 658.80 ± 0.54 Ma for a tuff layer in the same region of South China, indicating a series of volcanic eruptions, bracketing the end of the Sturtian glaciation, that lasted over 1.5 to 4.7 Ma. Taken together with ages for globally stratigraphically correlative units, it suggests that volcanism occurred at the end of the Sturtian glaciation and in its aftermath as a series of discrete events that lasted for at least 3.4 to 5.1 Ma. Widespread Fe-Mn-rich deposits in the glacial aftermath are also consistent with extensive submarine mafic volcanism during the Sturtian glaciation and its aftermath. Combined submarine mafic and subaerial felsic volcanism at the end of the Sturtian glaciation and in its immediate aftermath and a ca. 715–615 Ma gap in the record of Large Igneous Provinces argue for the contemporaneous arc and mid-ocean ridge magmatism as a trigger for the termination of the Sturtian glaciation. Our findings highlight feedbacks among the Cryogenian extreme climatic changes and global volcanic events as well as seawater Fe and Mn cycles.