[Mg/Fe] (upper panel) and [Ca/Fe] (middle panel) abundance ratios, and age as a function of [Fe/H] (lower panel) for main body clusters (turquoise filled circles), confirmed members (yellow filled hexagons), and good/interesting candidate members (brown filled squares), from Table 1. Upper and middle panels: we plotted field stars in the central region of Sgr dSph in gray (including M 54, from Mucciarelli et al. 2017); lower panel: we plotted, in orange triangles, the age and metallicity of the two main components of the Sgr field stars in the nuclear region (from Table 1 of Alfaro-Cuello et al. 2019), for comparison.