Amphibolitic Cu-Fe skarn deposits in the central coast of Peru

Monterrosas, Eliana, Raul, and Condestable are the most important copper mines in the central coast of Peru, between lat 12°30′ and 14°30′S. Their related geologic setting, close age relation, and similar mineralogy and geochemistry argue in favor of their grouping together as amphibolitic Cu-Fe skarn deposits. The geologic setting, petrography and major element chemistry of the deposits is discussed. Lead isotope compositions of chalcopyrite, pyrite, and galena define a primitive trend for these skarn deposits compared to that of porphyry Cu deposits in southern Peru and Chile and Sn deposits in Bolivia. The isotopic contrast is interpreted as a result of rifting and extreme crustal thinning during the Lower Cretaceous along the continental margin of central and southern Peru. This tectonic and metallogenetic environment continued into northern and central Chile where amphibolitic Fe and Cu deposits of the same age range are known. -from Authors