The study of the [Mg/Fe] versus |z_max| relation with stellar ages < 8 Gyr. The grey points indicate stars with observed [Mg/Fe] abundance ratios for stars from APOGEE DR16 (Ahumada et al. 2020) in the Galactocentric region between 6 and 10 kpc as a function of the computed maximum vertical heights |z_max| with ages < 8 Gyr as reported in the astroNN catalogue. White diamonds stand for the median |z_max| and [Mg/Fe] values in bins of [Mg/Fe] with the same number of stars. The contour lines enclose fractions of 0.95, 0.90, 0.75, 0.60, 0.45, 0.30, 0.20, and 0.05 of the total number of observed stars. Stars with observed vertical heights of |z|< 2 kpc, |z|< 1 kpc, and |z|< 0.5 kpc are reported in the left, middle, and right panels, respectively. ES21 only model predictions for stars younger than 8 Gyr, including the J_z versus age relation by Ting & Rix (2019), which is indicated in each panel with the dashed black line. In the upper panels, the colour coding indicates the predicted surface stellar mass density ΔM_⋆ formed in age intervals of 0.05 Gyr. In lower panels, the colour-coded circles depict ages of new SSPs formed during the Galactic evolution in age intervals of 0.05 Gyr. Although the upper limit for the maximum vertical |z_max| in all panels has been fixed at a value of 3 kpc, excluding outlier stars, the median values and the contour density lines have been computed taking into account all the stars in the respective samples.