Andacollo copper-gold district, La Serena, Chile: Preliminary data from the porphyry copper and possible relationships between Cu and Au mineralization

The Andacollo mining district is located in the Coquimbo region of Chile at 30°14’ south, 71°06’ west, some 55 km southeast of La Serena, at a mean elevation of 1030 m within a semi-arid hilly landscape. Current mining activity in the district is concentrated on copper and gold. These metals are mined, respectively, from a porphyry copper deposit and epithermal, manto and vein gold deposits of adularia– sericite type. Other types of mineralization include mercury veins hosted by carbonate rocks. The gold veins are controlled by a northwest-trending set of normal faults, whereas the manto-type mineralization is strata-bound and largely confined to andesite breccias, dacites and sites of strong fracturing. The lateral and vertical continuity of the mantos is strongly controlled by rock type, faulting and intensity of fracturing. The gold deposits have been the focus of a recent study, but comparable information on the Andacollo porphyry has not become available. A brief, updated geological perception of the porphyry is now presented and possible relationships between the copper and gold deposits are analysed.
Depto. de Mineralogía y Petrología
Fac. de Ciencias Geológicas
TRUE
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