The research will document how regional shifts in paleoenvironmental conditions during the Proterozoic-Cambrian transition may have influenced the record of extinctions and radiations of early Metazoa. Recent work in South Australia has shown that the inferred gap between the last appearance of complex vendozoans or the Ediacaran fauna and the first appearance of Cambrian-aspect traces is, in part, artifactual. It is suggested that the two faunas are in close stratigraphic and, by influence, close temporal proximity. In order to test this observation, detailed stratigraphic and paleontologic analyses will focus on the exceptional exposures of the Ediacaran-Cambrian transition in the Flinders Rangers, South Australia. Two principal data sets will be developed: 1) genetic stratigraphic sequence reconstructions of the intervl comprising the Upper Rawnsley Quartzite/Ediacara Member of the Pound Subgroup (uppermost Proterozoic?), Uratanna Formation (uppermost Proterozoic?-Lower Cambrian) and Parachilna Formation (Lower Cambrian); and 2) fossil/lithofacies associations of Ediacaran and earliest Cambrian trace and body fossils. Integration of these two data sets will allow the reconstruction of time- environment histories of faunal occurrences and a test of the role that ancient environments have played in biasing this record. By attempting to separate artifactual from factual signatures within the record, this research will have important implications for efforts to establish the causes and timing of the apparent demise of the Ediacara fauna and the dramatic subsequent radiation of the Cambrian fauna. The results of this work will contritube to on-going efforts to determine if there is a link between latest Proterozoic/Early Cambrian faunal turnover and a variety of geochemical and lithostratigraphic anomalies in the rock record. In addition, this research will improve our current understanding of the stratigraphy of a globally- significant Precambrian-Cambrian boundary section.
