3D Joint Inversion of Scanning Magnetic Microscopy Data

Scanning magnetic microscopy (SMM) is a modern magnetometry technique that maps the magnetic anomalies resulting from small-scale variations of remanent magnetization within a sample. This information is vital to understand the origin of rock behavior in laboratory experiments and in larger scale magnetic surveys. To quantify the fine-scale remanent magnetization, we used 3D magnetic vector inversion to jointly invert SMM data collected both above and below a 5 mm-thick norite sample from the Bjerkreim-Sokndal layered intrusion in South Norway. The sample is from an area with a striking remanent aeromagnetic anomaly which shows a minimum of -13,000 nT below background in the high-resolution helicopter survey. Inversion results confirm bulk remanent magnetization measurements with calculated median magnetization intensities between 79 and 106 A/m and a strong preferred magnetization direction perpendicular to the slab plane. Furthermore, results indicate that the main source of natural remanent magnetization is in the pyroxenes.

Automated summary

Scanning Magnetic Microscopy (SMM) is an important magnetometry technique that helps us understand the origin of rock behavior. In this study, 3D magnetic vector inversion was used to quantify the remanent magnetization in a norite sample and it was found that the main source of magnetization is pyroxenes.