Pressure remanent magnetization (PRM) is acquired when a rock is compressed in the presence of a magnetic field. This process can take place in many different environments from impact and ejection processes in space, to burial and subsequent uplifting of terrestrial rocks. In this study, we systematically study the acquisition of PRM at different pressures and temperatures, using synthetic magnetite in four different grain sizes ranging from nearly single-domain to purely multidomain. The magnitude of the PRM acquired in a 300 μT field is, within error, independent of the domain state of the sample. We propose that the acquisition of a PRM is mainly driven by the magnetostriction of the magnetic material. We further show that compared to a thermal remanent magnetization, the acquisition of PRM in large multidomain grains can be quite efficient, and may represent a significant component of magnetization in low-temperature–high-pressure environments.
Bibliographical noteFunding Information:
We would like to thank Mike Jackson and Bruce Moskowitz for valuable discussions on the manuscript. Also, we would like to thank Sonia Tikoo, Nick Swanson-Hysell and Rich Harrison whose comments and suggestions helped improve the manuscript. This work was performed at the Institute for Rock Magnetism (IRM) at the University of Minnesota. The IRM is a U.S. National Multi-user Facility supported through the Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division, and by funding from the University of Minnesota. All the data used are listed in the references or archived in the database of the Institute for Rock Magnetism (irm.umn.edu). This is IRM publication (1816). M. W. R. Volk and J. M. Feinberg were supported by NSF-EAR-1620582.
- pressure remanence