Depletions of Mg, Si, and Fe in DLA systems plotted on a common scale of [Fe/H] metallicity defined in Sect. 6.2. Blue diamonds: results obtained by merging all the observational samples (Tables 4 − 6); molecular DLA systems are marked with red circles; proximated DLA systems with red triangles; the peculiar system at z_abs = 1.6265 in QSO 0142-100 is marked with a red square. The labels CD, WD, and WH indicate the typical values of Galactic ISM depletions in cool disk gas, warm disk gas, and warm halo gas, respectively (see Table 3).