The Permian - Triassic (Palaeozoic - Mesozoic) boundary marks the greatest mass extinction in the history of the Earth's biosphere, which is sometimes referred to as Great Dying. Correlation of the Permian - Triassic (P - T) boundary in Australia and Gondwana with global and northern hemisphere marine boundary sequences and the formal GSSP section is limited by the paucity of marine index fossils. Interpretation of non - biostratigraphic proxies for the P - T boundary in Australia is also difficult. In this project, the student (co-supervised by Ian Metcalfe, University of New England, and Bob Nicoll, Geoscience Australia), will perform time calibration of the P - T boundary by U-Pb analysis of zircons from volcanic rocks bracketing the boundary, using the modern high-precision analytical techniques and the methods of zircon treatment that eliminate the influence of inheritance and Pb loss, such as mechanical and chemical abrasion.

Whether the earth’s mantle is oxidising or reducing is of particular importance, because its oxidation state partially controls the nature of fluids present there. For example, in a reduced mantle, fluids may be methane + water – dominated, but in a more oxidised mantle they may be carbon dioxide + water dominated. Trace or minor amounts of fluid in the mantle exert a profound influence on the way the mantle partially melts to produce magma and consequently on the nature of the magmas produced and erupted or emplaced into the crust. It is possible to determine the oxidation state of the mantle from fragments of lithospheric material (garnet peridotite xenoliths) transported to the surface in some volcanic eruptions. However, this requires precise measurement of Fe3+/total Fe in the mineral garnet, and this is currently difficult using conventional microbeam analytical techniques. We are endeavouring to develop a new synchrotron-based technique called Fe K-edge XANES. This requires a series of well-characterised garnet samples for calibration, and the summer student involved in this project would be engaged in synthesising them using high pressure experimental equipment at RSES, and in the full characterisation of the experimental materials using sophisticated analytical techniques such as electronprobe microanalysis and X-ray diffraction. Subsequent involvement in synchrotron measurements may also be possible.

Ocean straits are narrow constrictions which separate marginal seas from oceans, such as the straits of Gibraltar, the Indonesian Throughflow and the Heads of Sydney Harbour. Straits therefore restrict the flow of water between different parts off the ocean. It follows that these straits play a key role in regulating flow of water, nutrients and pollutants around the ocean.

This project will exmine the fundamental fluid dynamics of flow through straits, and will apply these results to the ocean. The project may either be based on laboratory experiments, numerical simulation or a combination of the two. The student can expect to develop and implement a program of experiments to learn more about flow through straits, and to develop conceptual understanding of this important aspect of oceanography.

Contact the supervisor directly for more information.