Terrestrial crater analogues to guide Mars sample-return missions
On Earth, the impact cratering record is incomplete due to crustal recycling and global resurfacing and contrasts with the heavily cratered lunar and Martian surfaces. Terrestrial impact craters with basaltic target rocks constitute ideal analogues for planetary surfaces and must be studied to anticipate sample-return missions from Mars and other planets. My PhD project investigates in detail the geochemical processes occurring during and after hypervelocity impact events on a simple basaltic target. To disentangle target rock mixing, impact melting, volatilization, condensation, projectile contamination, and hydrothermal alteration, a unique multi-isotopic approach is applied, along with petrography and in-depth geochemistry, first to the ~1.88 km Lonar impact crater and then to singular impact spherules beds resulting from >10s km sized asteroid impacts on possibly basaltic crust during the Archean. The obtained results provide critical constraints for much anticipated Martian sample-return missions and a universal model for the evolution of planetary crusts. Ultimately, these interpretations have important ramifications on our understanding of the habitability of planets.
Basaltic impact craters, non-traditional isotope systems, Mars analogue
Steven Goderis & Philippe Claeys