South Australian U-Pb zircon (CA-ID-TIMS) age supports globally synchronous Sturtian deglaciation

Abstract

A central prediction of the Snowball Earth hypothesis is that glacial onset should be synchronous at low latitudes, and its termination should be rapid and synchronous globally. High precision U/Pb zircon ages provide supporting evidence for the synchronous onset (within error) of the Sturtian glaciation (ca. 716 Ma) on multiple continents. Successful application of Re-Os techniques on organic rich shales and carbonates allow for the possibility of a globally synchronous Sturtian deglaciation (ca. 660 Ma), but the sparse isotopic age constraints leave this open to debate. Here we report the first high precision U-Pb zircon age of 663.03 ± 0.11 Ma (2σ) for the end Sturtian recorded in the Wilyerpa Formation of South Australia. This age supports previously published ages and is permissive with a globally synchronous deglaciation. In conjunction with the timing of glacial onset, this age reinforces the ca. 58 Myr duration of the Sturtian Snowball.