Distribution of stars in the [Fe/H]-[α/Fe] plane as a function of age range (top to bottom plots). The orange curve is our model for the inner disk. Ages from 12 to 7 Gyr along this sequence are also indicated. The blue curve is the same in all plots and serves as a guide to show the shift of the distribution with age. The parallel sequences of different ages illustrate that chemical evolution in the solar vicinity (the OLR region) and beyond proceeded along evolutionary paths that link these sequences as age-metallicity sequences with the two sequences being of different age.