  We derived radial velocities and CaT metallicity of more than 150 red giants
stars in six SMC star clusters and their surrounding fields, with the
instrument GMOS on GEMINI-S. The mean cluster radial velocity and metallicity
were obtained with mean errors of 2.2 km\,s$^{-1}$ and 0.03 dex, while the mean
field metallicities have a mean error of 0.13 dex. We add this information to
that available for another 51 clusters and 30 fields with CaT metallicities on
the same scale. Using this expanded sample we analize the chemical properties
of the SMC Main Body, defined as the inner 3.4 degrees in semimajor axis. We
found a high probability that the metallicity distribution of the Main Body
clusters is bimodal with a metal-rich and a metal-poor cluster group, having
mean metallicities with a dispersion of $\mu = -0.80$, $\sigma = 0.06$ and $\mu
= -1.15$, $\sigma = 0.10$ dex, respectively. On the other hand, Main Body field
stars show a unimodal metallicity distribution peaking at $[Fe/H] \sim -1$ and
dispersion of $0.3$. Neither metal-rich nor metal-poor clusters present a
metallicity gradient. However the full Main Body cluster sample and field stars
have a negative metallicity gradient consistent with each other, but the one
corresponding to clusters has a large error due to the large metallicity
dispersion present in the clusters studied in that region. Metal-rich clusters
present a clear age-metallicity relation, while metal-poor clusters present no
chemical enrichment throughout the life of the galaxy. We present observational
evidence that the chemical enrichment is complex in the SMC Main Body. Two
cluster groups with potential different origins could be coexisting in the Main
Body. More data with precise and homogeneous metallicities and distances are
needed and dynamical simulations are required to understand possible different
origins for the two possible cluster groups.
