Neoproterozoic and Cambrian chemostratigraphic mega-sequences of the Officer Basin; a regional framework to assist petroleum and mineral exploration

Well and seismic correlation schemes exist for the Western Australian and South Australian parts of the Officer Basin but there are inconsistencies between the western and eastern regions. Hence, as part of the Exploring for the Future Officer-Musgrave Project, a chemostratigraphic correlation has been determined for the sedimentary fill of the Officer Basin with emphasis on Neoproterozoic to Cambrian rocks. The correlations have been developed on whole rock inorganic geochemical data obtained from the analysis of 10 study wells which span the basin from Western Australia and into South Australia. A total of 8 chemostratigraphic mega-sequences (MS) are recognised across the basin, that in turn are subdivided into a total of 24 chemostratigraphic sequences. MS1 to MS6 include the Neoproterozoic to Cambrian sedimentary rocks and are the focus of this study. The Neoproterozoic–Cambrian mega-sequences MS1 to MS4 broadly correspond to the previously defined Centralian supersequences CS1 to CS4 and provide robust well-control to the regional seismic correlations. Confidence in the correlation of these old rocks are important since they contain both potential source and reservoir rocks for petroleum generation and accumulation. MS7 is equivalent to the Permian Paterson Formation, while MS8 is equivalent to the Mesozoic section. The elemental data has also been used to elucidate aspects of the petroleum system by characterising reservoirs and identifying fine-grained siliciclastics deposited in anoxic environments which may have source potential. This work is expected to further improve geological knowledge and reduce the energy exploration risk of the Officer Basin, a key focus of this program. <b>Citation:</b> Edwards D.S., Munday S., Wang L., Riley D. & Khider K., 2022. Neoproterozoic and Cambrian chemostratigraphic mega-sequences of the Officer Basin; a regional framework to assist petroleum and mineral exploration. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146285