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

该项目将把世界上最大、最成功和相互独特的两个古地磁团体聚集在一起，以描述地球古代磁场的行为及其与地球深处动力学和演化的联系。合并利物浦和科廷现有的专业知识、采样目标和实验室设备的互补领域，有望产生一种新的长期合作，有可能帮助我们彻底改变对地球深处的了解。国际地磁研究所有一个长期研究计划，以生产和使用第一个基于经验的古地磁场行为(古地磁)定量模型，追溯到地球数十亿年的历史。这样做的动机是，这些将提供一个数值框架，用于了解地球发电机过程的物理学以及它如何随着地球的演化而变化(包括核和地幔的长期冷却、内核的成核和增长以及地幔对流引起的核幔热流的变化)。这些模型还将允许评估数值发电机模拟的真实性(包括那些在代表地球演化不同阶段的不同边界条件下运行的模拟)。最后，它们将提供一个工具，用于改善古地磁场测量对过去大陆重建和构造过程(经典古地磁学)的约束--这些目前依赖于关于时间平均场及其时间和空间变化的简单化假设。PI已经获得了大量资金，可以将这些模型建立到7.5亿年前，该项目旨在启动一项合作，将这项工作首先延伸到1.215亿年前，然后更远地追溯到前寒武纪。为了实现这一目标，我们需要：(I)获得750 Ma以前的可靠古地磁记录器的年代良好的岩石，以便能够产生高质量的全矢量古地磁记录；(Ii)发起一项密集的全球测量运动，从这些岩石中产生可靠的数据，这将约束古地磁行为的统计模型。(3)与世界领先的古地理学、经典古地磁学和地球动力学专家合作，适当描述前寒武纪古地磁场的行为，并利用这些信息改善我们对大陆表面构造及其与地球深部过程的关系的了解。我们的方法将是利用科廷可以获得的丰富资源(人力、技术和地质)，并分享利物浦开发的古地磁技术的工具和知识，从而启动一个新的对极古地磁场表征中心。在这个项目期间，我们将：(I)对已知行为可靠并共享现有样本的澳大利亚前寒武纪岩石进行现场合作采样；(Ii)进行互访，以相互教授我们各自的学科，在两个机构获得测量结果，分享目标和结果，并讨论未来的采样目标和项目；(Iii)利用元古代大陆重建来改进我们的全球统计场模型，并迭代预测重建可能如何随着古地磁场的变化而变化。该项目的成果将回答令人兴奋的研究问题，并及时启动一项重大的新合作，以利用现有的NERC和其他英国资金，并利用旨在产生古地磁研究新的世界领先方向的额外资金。

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.