The stratigraphy and facies of the late Precambrian at Ediacara, South Australia

Abstract

Abstract The facies of the Upper Member of the Pound Quartzite (late Precambrian) in the Ediacara Hills are described. Three principal facies are recognised: (1) The cross‐stratified and flat‐stratified sandstone facies, interpreted as offshore marine sands. (2) The main fossiliferous horizon, thin‐bedded sandstones with subsidiary siltstones, has gradational boundaries with (1). It represents a local de‐positional environment of lower hydrodynamic energy, such as a restricted bay. (3) A massive indurated sandstone, with intraformational conglomerates, which is locally present at the top of the Pound Quartzite. This is interpreted as a channel‐fill sediment. The Pound Quartzite is disconformably followed by the Parachilna Formation (Cambrian) which is a transgressive bioturbated sandstone facies. The junction between the two is irregular and is burrowed in places. Insufficient evidence is available at present to determine the time represented by the break.