Eocene stratigraphic succession in the Eucla Basin of South Australia and correlation to major regional sea-level events

Using palynostratigraphy combined with analysis of lithostratigraphy and sedimentary facies of discontinuous outcrops and selected drillholes, we have investigated whether the Eocene sequences and their boundaries in the Eucla Basin of South Australia were synchronous with major sea-level events. The correlation of Eocene sequences and their boundaries in the eastern nearshore and onshore Eucla Basin indicates that these complex marine–nonmarine strata fall into four sequences or allostratigraphic packages that can be seen from the offshore basin to nearshore and onshore basin, including palaeovalleys. Key sedimentary surfaces (disconformities, a tidal/wave ravinement surface, transgressive surfaces, maximum flooding surfaces) bound the packages (including three new revised units) and are coincident with four third-order sequence boundaries. The eastern Eucla Basin stratigraphy accords with the general view of Eocene sea-level patterns and elucidates a stepwise evolution of marine and nonmarine environments.