Determining Ancient Field Intensities from Chemical Remanent Magnetisations in Rocks and Meteorites

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This research project is focused on how we can measure the ancient field intensity (palaeointensity) of the Solar System and geomagnetic fields. One way in which rocks and meteorites record the magnetic field is by acquiring a grain-growth chemical remanent magnetisation (CRM), where an external magnetic field is recorded as magnetic crystals grow in size. During this research project I will develop a Preisach-based method using only room-temperature measurements to determine the palaeointensity recorded by a grain-growth CRM. The method will be empirically tested using both synthetic samples induced with a CRM, and historical samples from Hawaii, previously identified as carrying a grain-growth CRM where the geomagnetic inducing field is known.Once developed, the method will be applied to meteorites, looking at magnetic remanence in chondritic meteorites, which have undergone chemical alteration and therefore carry a CRM. This allows investigation into early Solar System processes by using constraints on processes placed by the ancient magnetic field strengths determined.