Mesozoic Iron Oxide Copper-Gold Mineralization in the Central Andes and the Gondwana Supercontinent Breakup

Abstract

The Mesozoic deposits in the Central Andes, especially represented by the dominant iron oxide copper-gold (IOCG) mineralization in southern Peru and northern Chile coastal IOCG belt, has emerged as one of the major exploration targets in the Central Andes in the last two decades. These deposits mainly formed during the Middle-Late Jurassic and Early Cretaceous. The major Cu-rich IOCG deposits are located in the Early Cretaceous mineralization belt, which is also the main Phanerozoic example of this type of ore deposit. The Central Andean IOCG deposits lie in a linear array of interconnected Mesozoic continental margin rift basins that record a major phase of extension accompanying subduction along the western margin of Gondwana. The Mesozoic tectonic evolution of the Central Andes since the initial phase of IOCG mineralization can be subdivided into the following: the Tethyan period (165-155 Ma); the South Atlantic period (145-135 Ma) and the Pacific period (120-100 Ma). Central Andean IOCG mineralization was initiated in the Middle Jurassic (165-155 Ma), associated with the high-angle subduction of the Phoenix plate and coeval with the early stage of Gondwana breakup. Following a relatively weak tectonomagmatic stage (135-120 Ma), the peak in Meso-zoic IOCG deposits occurred during the inversion of extensional basins (120-100 Ma), corresponding to the final separation of African and South American tectonic plates.