Prof. Jürgen Oberst, PhD

Institut für Geodäsie und Geoinformationstechnik, Straße des 17. Juni 135

D-10623 Berlin, Tel.: +49 30-31479701, e-mail, juergen.oberst@tu-berlin.de

A4 Summary

Large impact basins are the most prominent landforms on the Moon. Basin-forming impactors delivered the vast majority of matter during the late-accretion phase of the early Earth-Moon system and, thus, may have significantly contributed to the volatile inventory of the terrestrial planets and the Moon. The lunar basins are the oldest and only remaining physical traces of this heavy bombardment. Additionally, they represent important time markers of the early history of the Earth-Moon system. We wish to (1) obtain a full inventory of lunar impact basins; (2) study their formation and subsequent modifications; (3) study the distribution of ejected material and impact melt; (4) study the mixing of ejecta in the megaregolith by impact gardening and estimate its fractional persistence at the lunar surface; and, finally, (5) estimate the energy (and mass) of the impactors as well as understand the character of the lunar environment at the time the basins formed. The project will also significantly contribute to the petrological and geochemical evaluation and radiometric dating of critical lunar samples by providing constraints on the correlation of Apollo specimens to large basin-forming impact events and their ejecting and emplacement history.