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We present Cu isotope data of hypogene and supergene minerals from the Late Paleocene Spence Cu-Mo porphyry in the Atacama Desert of northern Chile. Chalcopyrite displays a restricted range of delta Cu-65 values within the values reported for primary porphyry Cu sulfides (+ 0.28aEuro degrees to + 0.34aEuro degrees, n = 6). Supergene chalcocite samples show heavier and remarkably homogeneous delta Cu-65 values, between + 3.91aEuro degrees and + 3.95aEuro degrees (n = 6), consistent with previous models of Cu leaching and enrichment in porphyry systems. Secondary Cu minerals from the oxide zone show a wider range of composition, varying from + 1.28aEuro degrees and + 1.37aEuro degrees for chrysocolla (n = 6) to very light Cu isotope signatures reported for atacamite between -5.72aEuro degrees to -6.77aEuro degrees (n = 17). These data suggest redox cycling of Cu during supergene enrichment of the Spence Cu deposit, characterized by a first stage of supergene chalcocite formation from acidic, isotopically-heavy leach fluids of meteoric origin down-flowing in a semi-arid climate (44 to similar to 15-9 Ma). Reworking of the initial supergene copper assemblage, during the Pleistocene, by rising neutral and chlorine-rich deep formation waters under well-established hyper-arid climate conditions lead to the formation of atacamite with extremely fractionated Cu compositions. Essentially coeval chrysocolla formed by dissolution of atacamite during short episodes of wetter climatic conditions occurring in the latest Pleistocene.