Age as a function of [α/Fe] of the stars in our sample. The age distributions of stars binned in [α/Fe] are superposed on black dots representing stars in the sample. On each age distribution the three horizontal lines denote the 25th, 50th and 75th percentile. Long, thin tails extending to young ages are associated to the overmassive α-rich stars (see Sect. 5.2 for more details).