Frond-like fossils from the base of the late Precambrian Wilpena Group, South Australia

Abstract

Late Precambrian metazoan fossils are at present known from at least 23 different regions in Africa, Asia, Australia, Europe and North America1. The Ediacara fossil assemblage2,3 occurs widely in the Flinders Ranges, South Australia, near the base of the Rawnsley quartzite of the Pound Subgroup. This complex of soft-bodied organisms includes medusoid coelenterates, soft corals related to pennatulids, segmented worms, arthropods and other simple coelenterates4,5. Here I report the discovery of frond-like fossils comparable to those of the Ediacara assemblage more than 3,000 m stratigraphically below the Ediacara Member6 of the Pound Subgroup. This discovery supports the placement of the base of the Ediacaran5 in South Australia at the boundary of the Wilpena Group and the Umberatana Group, a stratigraphic level which marks the termination of late Proterozoic glaciation in the Adelaide Geosyncline.