Obtaining a high-latitude Southern Hemisphere Cretaceous record: Naturaliste Plateau and Mentelle Basin Virtual Site Survey

Understanding the mechanisms, feedbacks and time relationships that link climate dynamics between the polar regions and the tropics is of fundamental importance for reconstructing rapid climate change in the past, and hence improving predictions for the future. There is growing scientific evidence that the mid-Cretaceous super-greenhouse climate may have been interrupted by a series of short-lived glaciations. Such events would provide just this kind of data. However, there is a clear lack of drill core from high-latitude Southern Hemisphere oceans, where evidence of these possible glaciations will be best preserved. The only other exisiting IODP proposal to drill the Cretaceous in the high-latitude Southern Hemisphere is primarily structured to investigate a restricted basin and will not provide the required open ocean information necessary to understand effects on global climate. In this proposal we will examine in detail the existing seismic data from the Naturaliste Plateau and Mentelle Basin offshore Western Australia which, during the Cretaceous, was exposed to open ocean circulation on the Australia/Antarctica continental margin. The results of this work will create detailed maps of the geological evolution of the Naturaliste Plateau and Mentelle Basin, with particular emphasis on the Cretaceous interval. These maps will be used to determine the optimal site for drilling Cretaceous sediments and will form the basis for an IODP Full Proposal. The results from this project will also be used to support a proposal to the ICDP to drill a time-equivalent (and deeper) shallow marine and continental sequence in the southern Perth Basin, thus providing a land-basin transect and data contributing to our understanding of deep-time ocean-atmosphere interactions.