The disk populations in the [MG/H]-[FE/MG] plane

The disk populations' metal abundance degeneracy is shown to be considerabl y relaxed in a two-dimensional presentation of their chemical properties. A s such, the metallicities of a sample of nearby F- and G-stars are given in terms of magnesium abundances along the abscissa and iron-to-magnesium abu ndance ratios perpendicular to that. In combination with stellar age estima tes and kinematics the disk populations turn out to be fairly well separabl e in this abundance plane, which in turn allows to address a number of impo rtant issues on the Milky Way's history.