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

这个研究项目的重点是如何测量太阳系和地磁场的古场强(古强度)。岩石和陨石记录磁场的一种方式是通过获取颗粒生长的化学剩余磁化(CRM)，即随着磁性晶体尺寸的增大而记录外部磁场。在这个研究项目中，我将开发一种基于Preisach的方法，只使用室温测量来确定由颗粒生长CRM记录的古强度。该方法将使用合成样品和夏威夷的历史样品进行经验测试，这些样品之前被认为携带着颗粒生长的CRM，那里的地磁感应场是已知的。一旦开发出来，该方法将应用于陨石，观察球粒陨石中的剩磁，这些陨石经历了化学作用，因此携带了CRM。这使得对太阳系早期过程的研究可以通过对由古代磁场强度确定的过程施加的限制来进行。

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.