  Using a combination of th local-density approximtion (LDA) and dynamicla
mean-field theory (DMFT) calculations, we explore the correlated electronic
structure of a member of the layered Iron oxychalcogenide Na_{2}Fe_{2}OSe_{2}.
We find that the parent compund is a multi-orbital Mott insulator.
Surprisingly, and somewhat reminiscent of the doped high-T_{c} cuprates,
carrier localization is found to persist upon weak hole doping because the
chemical potential lies in a gap structure wit almost vanishing
density-of-states (DOS). On the other hand, in remarkable contrast, electron
doping drives an orbital-selective metallic phase (OSMP) with co-existing
pseudogapped (Mott localized) and itinerant carriers. These remarkably
contrasting behaviors in a single system thus stem from drastic electronic
reconstruction caused by large-scale transfe of dynamical spectral
weightinvolving states with distinct orbital character at low energies, putting
the Fe oxychalcogenidesneatly into the increasingly visible tendency of Fe-baed
systems as ones in orbital-selective Mott phases. We detail the implications of
our analysis, and discuss the nature and symmetry of the superconductive states
that may arise upon proper doping or pressurizing Na_{2}Fe_{2}OSe_{2}.
