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<p>Ore in the Kamoa-Kakula deposits (Democratic Republic of Congo) is dominated by fine-grained Cu sulfides disseminated in Cryogenian diamictite matrix and siltstone, commonly with coarsely crystalline sulfide-gangue ‘caps’ and ‘beards’ on larger clasts. In addition to sedimentary material, ore-zone matrix contains hypogene Cu-sulfides, and ore-stage haematite and sericite. The finest-grained part of ore-zone matrix consists of randomly distributed, randomly oriented, irregularly interlocking subequant matrix crystals, with equant sulfide phases in interstitial pores. Millimetric subvertical swaths of microfoliated ore-zone matrix adjacent to larger diamictite clasts are dominated by sericite and are characterised by elongation and depletion of tectosilicates, dolomite, and Cu-sulfides. Removal of material from sides of silt-sized detrital particles in foliated ore-zone matrix was accompanied by syntaxial precipitation at their tops and bottoms, indicating that during horizontal compression, fluid-mediated pressure-solution and reprecipitation produced grain elongation and alignment, mass transfer (~−30%), and Cu-depletion in microfoliated matrix. This process explains the transfer of sulfide and gangue material into low-pressure areas on the tops and bottoms of the larger clasts (‘caps’ and ‘beards’). Ore characteristics were therefore produced by two distinct events: ‘early’ disseminated ore emplaced into isotropic diamictite matrix prior to orogenic compression and ‘late’ transfer of Cu and gangue minerals from diamictite matrix into clast-caps during Lufilian (late Neoproterozoic) compression.</p>