Cryogenian-Ediacaran Carbon Isotope Stratigraphy of the Amadeus Basin, Central Australia

Abstract:

Deciphering the nature of extreme Neoproterozoic climatic and biogeochemical perturbations hinges on correlating sedimentary sequences within and across different basins. To improve these correlations within central Australia, we have focused on the abundant and laterally extensive glaciogenic and carbonate deposits of the Amadeus Basin. Here, we present new high-resolution carbonate C isotope profiles from Cryogenian-Ediacaran stratigraphic successions (the Areyonga, Aralka, Olympic, and Julie Formations) that are particularly well exposed in the northeastern part of the basin. The data appear to span a duration of >100 Ma, from the end of the older Cryogenian glaciation to the upper Ediacaran. In addition to major isotopic excursions resembling those described from other Neoproterozoic successions, the Amadeus Basin isotopic profiles display consistent fine-scale patterns and lateral trends that allow us to identify diachronous strata and refine the overall stratigraphic and tectonic architecture of the basin.