The Candelaria (Cu-Fe-Au) and Punta del Cobre (Cu-Fe) deposits (Copiapo, Chile): a case for extension-related granitoid emplacement and mineralization processes?

Abstract

The Lower Cretaceous volcanic formations of Copiapó (Chile) host major stratiform, disseminated, vein, and stockwork mineral deposits. Among these are the Punta del Cobre district (Cu-Fe) and the neighbouring, large Candelaria deposit (Cu-Fe-Au). These deposits are likely to have formed during a major extensional event that was accompanied by granitoid emplacement that triggered important contact metamorphism, metasomatic activity and mineralization processes. We suggest here that alteration-mineralization processes developed within the upper-plate domain of a NNE-trending, ESE-dipping extensional system, while granitoids were accomodated within the lower-plate. If this model prove to be right, `Candelaria-type' deposits may be hidden beneath the present, higher structural position of the Punta del Cobre district.