Geophysics involves the use of indirect imaging techniques to constrain the present-day architecture of the ground beneath our feet. Important examples include seismic tomography, whereby the velocity of seismic waves travelling though Earth's interior are used to image key geometries and interfaces, and magnetotelluric studies, where the electrical and magnetic response of the solid Earth to solar flares and lighting strikes is measured to infer variations in its temperature and composition. At RSES, we use these methods and many more to build up quantitative pictures across scales ranging from a few tens of meters (e.g. the geometry of shallow ore deposits) up to hundreds of kilometers (e.g. the locations of subducted oceanic crust and upwelling mantle plumes). A good example of this type of research comes from our work on lithospheric architecture and mineral systems.

The lithosphere is composed of two layers – the crust and the underlying rigid, outermost portion of the mantle. Together, they form strong, tectonic plates that translate laterally across the surface of the convecting mantle. Lithospheric architecture therefore plays a key role in localising where deformation occurs, controlling the distribution of earthquakes, volcanoes, sedimentary basins, mountain ranges, and subduction zones. Since virtually all mineral deposits are formed in these geodynamic settings, mapping the present-day architecture of Earth’s lithosphere is fundamental to successful exploration for critical minerals.

At RSES, we are undertaking a number of diverse research projects aimed at improving our knowledge of lithospheric structure and its relationship to mineralisation. We use geophysical methods to image crustal thickness variations and density structure. We analyse the geochemistry of mantle xenoliths and develop thermobarometric techniques to constrain paleo-thermal structure and variations in depletion and metasomatism. We integrate seismic tomography models, magnetotelluric studies, and rock-deformation experiments to build 3-D models of the mantle lithosphere. Collectively, the goal of this interdisciplinary research is to better understand the spatiotemporal evolution of the lithosphere and how cryptic geodynamic processes such as depletion and metasomatism have modified the distribution of critical elements over time.

Models developed at RSES are used to inform ongoing mineral exploration efforts in Australia and elsewhere. For example, we produced a number of key datasets used to develop mineral prospectivity maps by Geoscience Australia during the Exploring for the Future program. We work with partners from across academia, industry, state, and Commonwealth agencies and are always open to new collaborations.