Professor Richard Harrison

NanoPaleoMagnetism: A Multi-Scale Approach to Paleomagnetic Analysis of Geological Materials

Paleomagnetism has played a pivotal role in developing our modern understanding of the Earth, and continues to be one of the primary tools used by Earth scientists to study the structure, dynamics and geological history of our planet. Despite the importance of paleomagnetic observations, however, numerous factors can be detrimental to the fidelity of magnetic information recorded by a rock. Ultimately, these factors restrict our confidence in geological theories that rely heavily on paleomagnetic evidence.

Paleomagnetic information is, like the magnetic information stored on a computer’s hard drive, susceptible to data loss and corruption over time. The older the rock, the more complex is its geological history, and the more likely it is to have experienced conditions (e.g. metamorphic heating, exposure to geothermal fluids, groundwater and biogeochemical processes) that altered, or even destroyed, its primary magnetic information. Consequently, some of the most interesting and controversial periods of Earth’s history occur far beyond the current limits of our confidence in the paleomagnetic signals used to study them. The problem of paleomagnetic reliability gets dramatically worse when it comes to extraterrestrial materials, such as meteorites, that predate the formation of the Earth itself. 

Dr. Richard Harrison is head of the the NanoPaleoMagnetism group, which aims to develop the scientific and technological basis for a multiscale approach to paleomagnetism, that tackles directly the issue of reliability and confidence in paleomagnetic measurements of such challenging samples. The approach adopts recent technological developments within the fields of solid state physics and materials science to provide a detailed chemical, microstructural and magnetic analysis of microscale regions of interest with nanoscale spatial resolution. The information obtained is used to develop a comprehensive physical model of the sample that establishes a quantitative link between nanoscale and microscale magnetic behaviour. The aims of this integrated experimental and computational approach is to quantify and interpret magnetic remanence carried by ancient or severely altered rocks, massively expanding the range of materials suitable for paleomagnetic study and thereby opening up entirely new avenues of scientific enquiry.

To learn more about the NanoPaleoMag project, please visit the NanoPaleoMag Group Website.