Constraints on the origin of the sources of lunar magnetic anomalies from orbital magnetic field data

Magnetic field anomalies of crustal origin are found to be heterogeneously distributed over the entire lunar surface. Except for few specific cases, in general the magnetic field anomalies are not related to known geological structures. Therefore, the origin of many anomalies sources is still debated, and various possible mechanisms have been proposed. Impactors contamination that could deliver iron-rich material to the lunar surface, or heating associated with magmatic activity that could alter rocks into strong magnetic carriers, are some of the current suggestions to explain the source origin. In any case, it is accepted that the inducing field that magnetized the lunar crust was a global magnetic field generated by a core dynamo. In order to get insights on the time evolution of the lunar dynamo, it is important to know when and how each magnetic anomaly was formed. Generally, only specific anomalies related either to swirls, or to impact craters are used for such investigations. This is because assumptions on the source geometry are typically made to explain the observed field anomaly. In this work, we aim constrain the origin of random magnetic anomaly sources using orbital magnetic field data without making any a priori geometry assumption.