The mid-Cretaceous volcano-sedimentary sequences of the Casma Group in Central Peru hosts several Volcanic Hosted Massive Sulphide (VHMS) deposits. The main mine is on the Petubar Ba-ZnPb VHMS deposit, formed by the Graciela, Juanita, Cecilia Norte and Cecilia Sur massive sulphide (±barite) bodies. The stratigraphy of the Casma Group at Peru bar consists of four units, mainly composed of submarine volcanic rocks and pyroclastic deposits ranging from basaltic-andesitic to rhyodacitic composition, intercalated with volcaniclastic sandstones, tuffaceous mudstones, siltstones, and impure limestones. The massive sulphide lenses are found on top of an impure limestone interval and in close spatial association with andesitic to rhyodacitic lavas, hyaloclastites and pyroclastic rocks. The Perubar deposit was strongly dislocated shortly after its deposition following an active faultblock subsidence event. Massive sulphide lenses were separated from their main feeder zones and partly mobilized along the margin of deeply subsiding blocks. Once put back in its original position the Perubar VHMS deposit presents a typical proximal-to-distal zonation, from: (i) pyrite-pyrrhotitesphalerite(+rare chalcopyrite) stockwork, (ii) massive pyrite-pyrrhotite-magnetite, (iii) massive Zn, (Fe>Pb) sulphides (±barite), (iv) banded barite and Zn, (Fe>Pb) sulphides, and (v) banded barite pyrite. Typical footwall hydrothermal alteration zones have been recognized and range from a strongly chloritized-sericitized core to a peripheral extensive quartz-sericite alteration zone. The geological evolution recorded in the Casma rocks of the Cocachacra district suggest the existence of a local submarine caldera system at Perubar. The deposit probably formed at shallow water depth (<500 m?), as indicated by the presence of limestones in the basin at the time of mineralization.