Sources of Clasts in Terrestrial Impact Melts: Clues to the Origin of LKFM

Abstract

Low-K Fra Mauro (LKFM) ''basalt," which is found exclusively as an impact melt rock, cannot be modeled geochemically from its clast population or from any combination of known pristine lunar rock types; there is a missing component enriched in both KREEP and transition metals (e.g., TI and Sc). To clarify clast/melt relationships, we studied impact melt rocks from Mistastin Lake crater, Labrador, Canada, where there are only three target rocks: anorthosite, quartz monzonite, and granodiorite.