By exciting the M shell of atomic zinc in the 80-110-eV photon energy range with synchrotron radiation, and by using photoelectron and photoion detection, we have located the 3p'3d' 4s ns (and nd} excited states in the 91-99-eV region. Resonant satellites are observed, allowing us to demonstrate the dominant role played by the 3p 'ns'~3d~n lef interaction upon the decay of the 3p~ns excited states. The 3p 'ns'~3d 2n'tef super-Coster-Kronig processes produce a large broadening of the 3p excited states which form series of overlapping states. The resonant satellites lying in the high-energy region are singly ionized states of 3p 3d'4s'n'I configurations, which autoionize into the various 3p 3d 4p or 3p 3d 4s states of Zn +. Ab initio calculations using intermediate coupling have been performed and display good quantitative agreement with the experimental results. PACS number(s): 32.80.Hd, 32.80.Fb, 32.80.Dz, 31.50.+w