We collected samples from nine different paired stones of NWA 7034, a Martian meteorite which has minerals dated to be 4.4 billion years old. According to our measurements, all samples have been exposed to strong hand magnets on Earth, a widely used meteorite identification technique which leads to the destruction of their magnetic record. In order to raise awareness around this issue, we performed a comprehensive study of the effect of magnets on the magnetic record of rocks, through numerical modeling and a controlled remagnetization experiment.
This study has been published at the peer-reviewed Journal of Geophysical Research (JGR), highlighted by the editors of JGR in Eos (the science news magazine published by the American Geophysical Union), presented at the 28th IUGG General Assembly that took place in July 2023 in Berlin, Germany, and received widespread media attention (Science Magazine, MIT News, Sky&Telescope and others). It is also the subject of a comic book I put together in collaboration with scientific illustrator Dr. Sabrina Sanchez. It is available on my website and we will present it at the European Geosciences Union (EGU) General Assembly in Vienna, Austria, in April 2024.
Further on, I conducted two paleomagnetic studies using lunar samples of the Apollo 16 and Apollo 17 missions. These rocks span two billion years of lunar history, with ages ranging from 3.7 to 1.7 billion years old. I conducted laboratory measurements in order to obtain paleointensity estimates (i.e. estimates about the strength of the lunar magnetic field) and rock magnetic measurements in order to characterize their magnetic properties. According to these studies, the lunar magnetic field at 3.7 Gy ago was approximately 40 μT, by 3.4 Gy it has dropped to below 6 μT and by 1.7 Gy ago it was less than 2 μT and possibly zero. These results, in combination with previous studies, suggest that the lunar magnetic field intensity has been fluctuating at least since 3.4 Gy ago.
The results of the Apollo 17 mare basalts have been presented at the AGU Fall meeting 2021 in New Orleans, USA and the results of the Apollo 16 regolith breccias have been presented at the LPSC 2023 in Texas, USA. I am currently working on the respective papers to be submitted to peer-reviewed journals. I also presented the main results at a seminar at IPGP, France and I will present them at an invited talk at the EGU General Assembly in Vienna, Austria, in April 2024.
I also worked on two different inversion methodologies, which can convert spacecraft magnetic field measurements into information about the magnetization of the underlying sources.
Firstly, I developed a new such inversion methodology that allows us to infer the direction of the magnetization from a local set of magnetic field measurements. I presented this novel inversion technique at the AGU Fall meeting 2020 (virtual conference).
Secondly, in collaboration with Marie Curie fellow Dr. Joana Oliveira, we evaluated the potential of an existing inversion technique for inferring the geometry of magnetic sources. We found that this method successfully localizes and delineates the two-dimensional surface projection of subsurface three-dimensional magnetized bodies. We used it to decipher the origin of two lunar magnetic anomalies. This study has been published at the peer-reviewed Journal of Geophysical Research.
