The Pinaya district hosts porphyry Cu–Au mineralization in the Pinaya deposit and other mineralized centers. Cu–Au mineralization is contained in quartz stockworks with chalcopyrite and bornite associated with potassic alteration in early to intermineral daci-andesitic dikes and irregular intrusions emplaced within terrigenous facies of the Puno Group. Prograde, garnet-skarn formed in adjacent, carbonate-bearing host rocks, likely simultaneously with the potassic alteration of the productive intrusions. Both potassic and skarn associations were overprinted by progressive hydrolytic phases of sericite-clay and dickite-dominated weak and fracture-controlled advanced argillic alteration. The first was predominantly pyritic, but the second introduced localized chalcocite, digenite, and covellite in addition to pyrite in a high to very high-sulfidation environment. A later, porphyry-centered event of intermediate-sulfidation mineralization formed proximal quartz-adularia containing nominal amounts of precious metals and distal polymetallic veins. Supergene alteration and mineralization produced an irregular profile with mixed oxide-sulfides and supergene chalcocite.The age of the porphyry-related magmatism is bracketed by two U–Pb (zircon) dates of ∼28 Ma on early and intermineral porphyry phases. This age and the associated trace-element signature of the host intrusions (Sr, V, Sc) not only indicate that Pinaya was emplaced late in the evolution of the larger Andahuaylas-Yauri porphyry-skarn metallogenic belt, but also confirms that it can be confidently extended for ∼60 km to the south. It is proposed here that porphyry Cu–Au mineralization at Pinaya was emplaced at the transition from the flat-slab subduction that characterized the evolution of the Andahuaylas-Yauri batholith and related metallogeny to normal-slab subduction at 28 Ma.