Evolution of the Exmouth-Barrow carbonate margin through the Miocene: Insights from 3D seismic data and field investigations (North West Shelf, Australia)

Carbonate margins are records of the palaeoclimatology, palaeoceanography and palaeogeography of continental shelves, and their study can help identify both regional and global palaeoenvironmental changes. This study documents the evolution of the Exmouth-Barrow margin, which records one of the largest ramp to rimmed platform transition documented yet, throughout the Miocene. The research is based on the integration of onshore outcrops, offshore wells and 3D seismic data. The margin evolution can be divided in four main phases, including: (1) progradation of carbonate clinoforms, forming a depositional ramp, during the early Miocene; (2) sabkha development and extensive dolomitization, concomitant with the Miocene Climatic Optimum; (3) formation of a carbonate barrier-lagoon system associated with slope channels during the middle Miocene; and (4) onset of a dominantly siliciclastic sedimentation from the end of middle Miocene onward. Overall, this study illustrates how outcrops and offshore seismic data can be integrated to reconstruct the regional stratigraphic and palaeoenvironmental evolution of a continental margin, with outcrops providing precise but local information, while 3D seismic data allow the basin-scale reconstruction of the palaeolandscape.