Left: clustercentric radius vs. line-of-sight velocity for the R2248 cluster members. The red symbols located at a clustercentric radius R <  R₅₀₀ are considered to be accreted and possibly virialised cluster members, which are in dynamical equilibrium with the clusters’ gravitational potential. The blue symbols located at a clustercentric radius R >  R₅₀₀ are classified as infalling galaxies, which have been just recently accreted onto the cluster. The dashed black line stands for R₅₀₀. The large points represent the galaxies with middle-resolution observations, while the smaller, fainter points represent the entire sample of CLASH VIMOS R2248 galaxies, which were observed with a low-resolution grism. The dark grey-shaded region encompasses the 1σ contours of the caustic profile, while the light-grey shaded area encompasses the 1σ − 2σ contours. Right: MZR comparison between field galaxies, represented by the black open symbols, and the R2248 cluster members with different accretion histories: the red and blue symbols represent the accreted and infalling cluster members, respectively. Only galaxies from the “mass complete” bin (9.2 <  log(M/M_⊙) < 10.2) are considered. The median values for the gas phase metallicities of the three samples are shown as the large symbols, colour coded accordingly. The magenta curves and diamonds show the local SDSS relation as derived using the O3N2 calibration. The median (O/H) value of the accreted cluster galaxies is by 0.04 dex higher than that of the infalling cluster galaxies, and by 0.085 dex higher than that of the field galaxies.