Geodynamic history of the Moon and Mercury revealed by their volcano-tectonic record and gravity field

• Applicant: Dr. Adrien Broquet
• Subject Area: Geophysics ; Astrophysics and Astronomy
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559317179

The project integrates satellite observations, geophysical modelling, and supervised learning techniques to unravel the volcano-tectonic histories of Mercury and the Moon. Advances in theoretical geophysics, particularly in interior and gravity modelling, are developed in connection with upcoming space missions to these bodies. Building on insights from the extensively explored Moon, these developments are directly applicable to the exploration of the inner solar system and beyond. The origin of tectonic structures on the surface of Mercury remains one of the most important enigmas in planetary science. In the first part of this proposal, neural networks will be developed to map and classify thousands of tectonic structures and allow an in-depth probabilistic discussion of their origin. This approach represents a major advance in planetary tectonics. Modelling of crustal deformations, as recorded in the gravity field and planetary topography, will complement this analysis. This hybrid approach will provide a new perspective on the geodynamic evolution of Mercury and unravel its thermal history, with broader implications for the geologic evolution of the terrestrial planets. On the Moon, the eruption history of the maria and the source of mare volcanism have surprisingly remained enigmatic and poorly modelled. The second part of this proposal aims to develop a geophysical model coupling mare emplacement and subsequent flow, together with surface deformation. The origin of graben and wrinkle ridges systems at the margin of large mare basins will also be explored, by considering the viscoelastic relaxation of the basin crustal structure. This will allow to place constraints on the thermal state of the Moon at the dawn of its geologic history and better characterize volcanism and basin evolution, two fundamental geological process that affected all terrestrial planets. Finally, the project develops theoretical advances in planetary geophysics in the framework of upcoming space missions using the generally better explored Moon as a sandbox testing environment. Accounting for the effects of planetary mantle convection on crustal thickness modelling based on observed gravity data, will enhance both thermal evolution models and crustal thickness estimates. Advanced methods for gravity mapping are also developed, featuring a new improved gravity field estimation approach that leverages orbital observations and machine learning techniques. This approach, which uses more data than previous work and proposes learning on known data, will have a major impact on gravity modelling of rocky bodies. Establishing a state-of-the-art research group focused on planetary tectonics and volcanism will significantly enhance Germany’s existing expertise in space research. This initiative will further stimulate academic progress and promote broader exploration of these topics.

• DFG Programme: Emmy Noether Independent Junior Research Groups