DEEP down under: The potential for UK-Australian Palaeomagnetism to contribute to a new paradigm in deep Earth studies

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This project will bring together two of the world's largest, most successful, and mutually distinctive palaeomagnetic groups to characterise the behaviour of Earth's ancient magnetic field and its link with deep Earth dynamics and evolution. Merging the complementary areas of expertise, sampling targets, and laboratory equipment available at Liverpool and Curtin promises to generate a novel longstanding collaboration with the potential to help revolutionise our understanding of Earth's deep interior. The PI has a long term research plan to produce and use the first empirically-based quantitative models of palaeomagnetic field behaviour (palaeo-geomagnetism) back across billions of years of Earth history. The motivation for this is that these will provide a numerical framework for understanding the physics of the geodynamo process and how it has changed with Earth's evolution (including secular cooling of the core and mantle, inner core nucleation and growth, and changes in core-mantle heat flux resulting from mantle convection). These models will also allow assessments to made of the realism of numerical dynamo simulations (including those running under different boundary conditions representing different stages in Earth's evolution). Finally they will provide a tool for improving the constraints provided by measurements of the palaeomagnetic field on past continental reconstructions and tectonic processes (classical palaeomagnetism) - these currently rely on simplistic assumptions concerning the time-averaged field and its variability in time and space.The PI has already secured substantial funding to build these models back to 750 million years ago and this project is designed to initiate a collaboration that will extend this endeavour firstly back to 1215 million years ago and then farther back into the Precambrian. In order to achieve this, we need to: (i) Obtain access to well-dated rocks from before 750 Ma that are reliable palaeomagnetic recorders to enable high quality full vector palaeo-geomagnetic records to be produced (ii) Initiate an intensive global measurement campaign to generate reliable data from such rocks that will constrain the statistical models of palaeo-geomagnetic field behaviour. (iii) Undertake collaborations with world-leading specialists in palaeogeography, classical palaeomagnetism and geodynamics to properly characterise Precambrian palaeo-geomagnetic field behaviour and exploit this information to improve our understanding of continental configurations at its surface and its relationship with deep Earth processes.Our approach will be to utilise the wealth of resources (human, technical and geological) accessible to Curtin and to share the tools and knowledge of palaeo-geomagnetic technqiues developed at Liverpool such that a new antipodal centre of excellence in palaeo-geomagnetic field characterisation is initiated. During this project, we will: (i) undertake collaborative field sampling of Australian Precambrian rocks that are known to behave reliably and share extant samples; (ii) perform reciprocal visits to teach one another about our respective disciplines, obtain measurements at both institutions, share goals and results, and discuss future sampling targets and projects; (iii) use Proterozoic continental reconstructions to improve our global statistical field models and iterate to predict how reconstructions might change as a consequence of how the palaeomagnetic field varied. The outcomes of this project will answer exciting research questions and kick-start a major new collaboration in a timely manner to capitalise on existing NERC and other UK funding and leverage additional funds aimed at producing a new world leading direction in palaeo-geomagnetic research.