TY - JOUR A1 - Höhn, Stefan A1 - Frimmel, Hartwig E. A1 - Debaille, Vinciane A1 - Price, Westley T1 - Pre‐Klondikean oxidation prepared the ground for Broken Hill‐type mineralization in South Africa T2 - Terra Nova N2 - New Cu isotope data obtained on chalcopyrite from the Black Mountain and the Broken Hill deposits in the medium‐ to high‐grade metamorphic Aggeneys‐Gamsberg ore district (South Africa) require a revision of our understanding of the genesis of metamorphic Broken Hill‐type massive sulphide deposits. Chalcopyrite from both deposits revealed unusually wide ranges in δ\(^{65}\)Cu (−2.41 to 2.84‰ NIST 976 standard) in combination with distinctly positive mean values (0.27 and 0.94‰, respectively). This is interpreted to reflect derivation from various silicate and oxide precursor minerals in which Cu occurred in higher oxidation states. Together with the observation of a typical supergene base metal distribution within the deposits and their spatial association with an unconformity only meters above the ore horizon, our new data are best explained by supergene oxidation of originally possibly SEDEX deposits prior to metamorphic sulphide formation, between the Okiepian (1,210–1,180 Ma) and Klondikean (1,040–1,020 Ma) orogenic events. KW - South Africa KW - mineralization KW - Broken Hill Y1 - 2021 UR - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/21854 UR - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-218545 VL - 33 IS - 2 SP - 168 EP - 173 ER -