Recent modeling by Steve Mojzsis and colleagues suggests that the large volume of impactors during the late accretion phase almost entirely resurfaced Mercury. This material induced extensive melting (~58%) of Mercury’s crust, which reworked the rocks of the crust and generated enough heat to make magnesium-rich melt. This would explain the high-magnesium content of the crust observed by MESSENGER. The heat flux and crustal melting also helped erase the oldest craters on Mercury, which is consistent with the currently observed crater statistics. READ MORE »