Age relationships of the Rembrandt basin and Enterprise Rupes, Mercury

Abstract

AbstractThe Rembrandt basin is the largest well-preserved impact feature in the southern hemisphere of Mercury. Its smooth volcanic infill hosts wrinkle ridges and graben, and the entire basin is cross-cut by the Enterprise Rupes scarp system. On the basis of the Model Production Function crater chronology, our analysis shows that the formation of the Rembrandt basin occurred at 3.8±0.1 Ga during the Late Heavy Bombardment, consistent with previous studies. We also find that the smooth plains interior to the basin were emplaced between 3.7 and 3.6±0.1 Ga, indicative of a resurfacing event within the Rembrandt basin that is consistent with the presence of partially buried craters. These youngest plains appear temporally unrelated to basin formation, and so we regard their origin as likely to be due to volcanism. We identify the same chronological relationship for the terrain cross-cut by Enterprise Rupes to the west of the basin. Therefore, volcanic activity affected both the basin and its surroundings, but ended prior to the majority of basin- and regional-scale tectonic deformation. If Enterprise Rupes formed prior to the Rembrandt basin, then regional-scale tectonic activity along this structure might have lasted at least 200 myr.