Abstract
GRAIL observations have been used to derive an updated catalog of lunar impact basins with diameters ≥ 450 km. In this study, we assess the age and relaxation state of these basins and find that the 13–15 stratigraphically younger basins are significantly less relaxed than the 8–16 identifiable older basins. The change in relaxation state is most likely a signature of the cooling of the base of the lunar crust below 1300–1400 K, which we infer happened between 4.21–4.45 Ga based on geochronological measurements. We compare the predicted number of basins before and after this reference point with several different modeled lunar cratering chronologies. While these models are sensitive to the ratio of 1km:450 km craters, we conclude that a model with a broad period of late heavy bombardment (a “sawtooth”) is more likely to fit both the number of relaxed and unrelaxed basins, and the mass of material delivered as a late veneer.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.