Archaeocyatha and the biostratigraphy of the lower Cambrian Hawker Group, South Australia

Abstract

Abstract Lower Cambrian strata in the Adelaide Geosyncline in South Australia contain rich faunas of Archaeocyatha. Recent Russian and French research has established a Lower Cambrian archaeocyathan faunal succession in Siberia, Europe and Africa, enabling correlation with those areas. Restricted dispersal of the benthonic Archaeocyatha makes genera, rather than species, useful for intercontinental correlation. South Australian faunas described previously were not collected in sequence and are of limited biostratigraphic use. Four collections from strata associated with an archaeocyathan biohermal bank in the Hawker Group of the Flinders Ranges were studied: faunas from the older two collections are distinct from those of the younger two. Resultant intraregional correlations suggest the presence of other bioherms, including the Ajax Limestone in the classic Ajax Mine locality. The potential of archaeocyathans for intraregional correlation is confirmed. There are ten genera in common between the four colle...