The chronostratigraphy of protoplanet Vesta

摘要: In this paper we present a time-stratigraphic scheme and geologic time scale for the protoplanet Vesta, based on global mapping other analyses of NASA Dawn spacecraft data, complemented by insights gained from laboratory studies howardite–eucrite–diogenite (HED) meteorites geophysical modeling. On basis prominent impact structures their associated deposits, propose Vesta that consists four periods: Pre-Veneneian, Veneneian, Rheasilvian, Marcian. The Pre-Veneneian Period covers formation up to Veneneia event, 4.6 Ga >2.1 (using asteroid flux-derived chronology system) or 3.7 (under lunar-derived system). Veneneian span between Rheasilvia events, 1 (asteroid chronology) 3.5 (lunar-derived chronology), respectively. Rheasilvian Marcia Marcian event until present. age is still uncertain, but our current best estimates crater counts ejecta blanket suggest an 120 390 Ma, depending upon choice system used. Regardless, represents youngest major Vesta. Our proposed four-period is, first order, comparable those developed airless terrestrial bodies.