Constraints on the Origin of the Sources of Lunar Magnetic Anomalies from Orbital Magnetic Field Data
Abstract
Magnetic field anomalies of crustal origin are found to be heterogeneously distributed over the entire lunar surface. In general, the magnetic field anomalies are not related to known geological structures, and their origin is still debated. 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 sources origin. It is accepted that the inducing field that magnetized the lunar crust was a global magnetic field generated by a core dynamo, however. 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. In this work, we aim to constrain the origin of random magnetic anomaly sources using orbital magnetic field data without making any a priori geometry assumption. We invert for the crustal magnetization using a unidirectional model, to constrain the magnetization source geometry. We test the performance of this method in by conducting a variety of synthetic tests using magnetized bodies of different geometries, intended to represent the many possible magnetized source origin scenarios such as basis, dykes, and lava tubes. Preliminary synthetic tests show that the location of the dipoles having the strongest magnetic moments is found to coincide with the region where the magnetized volume is buried. Further inversion results using samples from our synthetic tests library will allow us to explore the effect of all input parameters on the correct determination of the sources location. This will allow us to place constraints on the source origin, including anomalies which are not related to swirls or impact craters. Analysis of many lunar magnetic anomalies will lead to new constraints on the origin of their sources, and some of which may be of value in constraining the evolution of the lunar dynamo.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P31C3446O
- Keywords:
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- 6205 Asteroids;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6230 Martian satellites;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6250 Moon;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS