The iron ore in the Cerro Negro Norte and Cerro lman mining districts is strongly enriched in gold as compared with the altered and unaltered andesitic wallrock. Both districts belong to the about 600 km long Cretaceous Iron Belt of the Chilean Coastal Range. The iron deposits are interpreted as formed by a near surface emplacement of an ore magma, dominated by the magnetite-apatite assemblage, and followed by hydrothermal activity. This activity resulted in wallrock alteration, deposition of hydrothermal iron ore ('stockwork' and disseminated types) around massive magnetite-apatite ores and generation of hydrothermal breccias. The altered wallrock displays a zoned arrangement around the iron deposits, with an internal halo of actinolitized rocks followed outwards by albitized rocks. An external halo of silicified +/- tourmalinized volcanic rocks is overprinting the actinolitized and albitized haloes. Based on field and textural relationships, two main hydrothermal events are suggested, the first one is characterized by high temperature solutions, neutral to slightly alkaline pH, rich in Mg, Fe, Ca, CO2, F, P, CI, which p reduced actinolitization and albitization in the wallrocks to the iron ore. A second overprinting stage, is produced by hydrothermal solutions of lower temperature, neutral to slightly acid pH, and rich in silica, F and B, resulting in an external halo of silicified +/- tourmalinized wallrocks. The distribution pattern of gold in magnetite and pyrite of the iron ores, along with the gold content in altered and unaltered wallrocks, suggest that generation of a magnetite-apatite ore magma may favor a primary gold concentration in magnetite during the magmatic stage. The hydrothermal activity associated with the iron ore emplacement, characterized by neutral to slightly alkaline solutions, rich in volatile, mainly CI, is capable of remobilizing the gold originally contained in magnetite, and potentially to produce economical gold concentrations.