My research program is generally problem-orientated and therefore spans a wide range of topics, crossing the traditional discipline boundaries of Earth sciences. It brings together data and models from across seismology, rock physics, geochemistry, sedimentology, geochronology, geomorphology and paleoclimate. It combines field observations, numerical modelling, high-performance computing, uncertainty propagation and statistics. I generally try to take an inverse approach to solving problems, whereby observational datasets are used to place constraints on unknown physical properties and parameters of the Earth. This research philosophy provides a platform to tackle a wide range of fascinating topics, but would be completely impossible without leadership and support from an incredible group of highly specialised and gifted collaborators across academia, government and industry.
The remainder of this page provides a brief overview of some of the research topics that I am currently working on at ANU. If there is anything that takes your interest, please don’t hesitate to get in touch! I am always on the lookout for potential students and/or collaborators.
Continental structure and mineralisation
What is the current structure of the continental lithosphere and how did it get like this? How have the many processes that have sculpted it interacted to affect the generation and preservation of mineral deposits? Exploring these intriguing questions requires approaches from a range of angles. Ongoing projects include:
- Using geochemistry on fragments of mantle rocks carried to the surface by volcanic eruptions (known as mantle xenoliths) to constrain the thermal and lithological structure of lithospheric plates at specific points in time.
- Combining seismic tomography, rock physics experiments on anelasticity, and numerical modelling of conductive heat flow to map the present-day thermal structure of the crust and lithospheric mantle.
- Integrating field observations of sediments in outcrop and drill core with numerical models of basin formation to investigate the tectonic setting and thermal histories of sedimentary basins and their mineral deposits.
Paleoclimate and sea-level change
How have ice sheets behaved during previous climatic warming events in Earth’s past? Can we understand the sea-level response and how it is modulated by solid-Earth structure? How might we leverage these insights to provide more robust estimates and uncertainties of future sea-level change? This broad umbrella of questions is linked to a number of current research projects:
- Characterising and correcting for geodynamic processes that are responsible for deflecting paleo sea-level markers over the intervening time period since their deposition.
- Using field observations and numerical models to reconstruct former sea levels during interglacials.
- Developing state-of-the-art numerical tools to model the viscoelastic deformation, gravitational and rotational feedbacks of ice-sheet melting on sea-level change.
- Propagating uncertainties from seismic tomography, rock physics, rheological models and ice-sheet simulations into sea-level forecasts.
Underground nuclear testing
In order to reduce the likelihood of harmful radioactive fallout, the Partial Test Ban Treaty of 1963 limited all future tests of nuclear weapons to being performed underground. Since then, international efforts to monitor nuclear tests have largely focused on identifying the seismic energy generated by large explosions. A central question in this research is how can we differentiate nuclear tests from naturally occurring earthquakes? Projects underway on this topic include:
- Exploiting the statistical properties of data populations on a hypersphere to differentiate between explosions and earthquakes using their respective seismic moment tensors.
- Propagating uncertainties from moment tensor inversion into seismic event identification.
Deep mantle structure and rheology
What is the density structure and rheological behaviour of the convecting mantle? How do these properties influence geodynamic processes such as landscape evolution, sea-level change, volcanism and the mantle heat budget? This extensive topic is the subject of a number of ongoing research projects:
- Constraining the present-day spatial distribution of dynamic topography and using the rock record to investigate its temporal evolution.
- Combining measurements of Earth’s gravity field, surface and core-mantle boundary topography to place constraints on the spatial extent and buoyancy of Large Low-Velocity Provinces in the deep mantle.
- Using mantle convection observations and the sea-level record to constrain viscoelastic behaviour of the mantle.
