  ~Deep photometric data in the V-, R-, I-, z- and K-bands for the cluster of
galaxies EIS 0048-2942 are used to investigate the properties of the galaxy
populations at z~0.64 in a field of 2.5x2.5 Mpc^2. The sample of candidate
cluster members (N = 171) is selected by the photometric redshift technique and
is complete up to I=22.5. Galaxies were classified as spheroids and disks
according to the shape of the light profile in the I-band, as parametrized by
the Sersic index. In both optical and NIR, spheroids define a sharp
colour-magnitude sequence, whose slope and zero points are consistent with a
high formation redshift (z_f > 2). The disk population occupies a different
region in the colour-magnitude diagram, having bluer colours with respect to
the red sequence. Interestingly, we find some level of mixing between the
properties of the two classes: some disks lie on the colour-magnitude sequence
or are redder, while some spheroids turn out to be bluer. The spatial
distribution of cluster galaxies show a clumpy structure, with a main
over-density of radius ~0.5 Mpc, and at least two other clumps distant ~1 Mpc
from the center. The various sub-structures are mostly populated by the red
galaxies, while the blue population has an almost uniform distribution. The
fraction of blue galaxies in EIS 0048-2942 is f_B=0.11 +/-0.07. This is much
lower than what expected on the basis of the Butcher-Oemler effect at lower
redshifts.
