Sabkha and playa environments in late Proterozoic grabens,Willouran Ranges,South Australia

We have reconstructed the depositional environment of sulphate‐dolomite‐sand‐mud sequences of the Callanna Beds of the late Proterozoic Adelaidean System in three areas of the Willouran Ranges, South Australia. We interpret the Callanna Beds which represent the earliest Adelaidean sediments as having been deposited in a series of discrete shallow cratonic basins. The sequences in all three areas consist of cyclic hypersaline sand‐shale‐carbonate sheets and wedges. Hypersalinity has been inferred from a study of evaporites and their pseudomorphs, which imply basin evolution in sabkha and playa palaeoenvironments. We interpret the Callanna Beds in the Willouran Ranges to have been formed in playa lake or prograding sabkha complexes, that formed in a series of yoked half‐grabens within the tectonic setting of the Adelaide palaeorift.