Patterns of distribution in the Ediacaran biotas: facies versus biogeography and evolution

The siliciclastic succession of the late Neoproterozoic Vendian Group in the White Sea area demonstrates a wide range of lithofacies, some recurring in a vertical succession. Significantly, each lithofacies contains a distinct assemblage of Ediacaran fossils that represents in situ benthic paleocommunities smothered in life position. These lithofacies define (1) a monospecific Inaria assemblage, restricted to the lower-shoreface muds; (2) a Charnia assemblage, within the middle-shoreface graded siltstone-shale couplets; (3) a Dickinsonia-Kimberella assemblage, confined to the interstratified sandstone and shale of prodelta; and (4) a Onegia-Rangea assemblage, preserved within channelized sandstone beds of the distributary-mouth bar. In the White Sea area a strong correlation exists between taxonomic composition, biostratinomic features, and paleoecological context of the Ediacaran fossil assemblages. Facies-controlled distribution is also evident in other Ediacaran localities, demonstrating the r...