Evolution of the Giant Marcona-Mina Justa Iron Oxide-Copper-Gold District, South-Central Peru

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

“…1.0 Ga (Loewy et al, 2004). The most voluminous units hosting the Andean Mesozoic deposits are Middle Jurassic to Lower Cretaceous volcanic-derived rocks generated in the arc and aborted marginal back-arc basins in southern Peru (Caldas, 1978;Romeuf et al, 1993) and northern Chile (Boric et al 1990;Grocott et al, 1994), both of which comprise basaltic andesitic to andesitic lava flows with subordinate volcaniclastic and marine sedimentary units (Aguirre, 1988;Sillitoe, 2003), and the Peruvian formations may have medium to high K calc-alkaline affinity (Aguirre, 1988;Romeuf et al 1993 Clark et al, 1990;Hawkes et al, 2002;Sillitoe, 2003;Oyarzun et al, 2003;Benavides et al, 2007;and Chen et al, 2010a). B.…”

“…1), approximately 70 km wide and extending discontinuously for 800 to 1,000 km along the Peruvian littoral from Lima to the Ilo-Ite area (Clark et al, 1990;Hawkes et al, 2002;Injoque, 2002;Chen et al, 2010a), developed in the Cañete basin and, to the south, along the axis of the Jurassic-Cretaceous shallow-marine volcano-plutonic arc. Ore deposits and mineral occurrences in this belt assignable to the IOCG clan include Raúl-Condestable, Eliana, Monterrosas, Mina Justa, Cobrepampa, Rosa María, Licona, Valparaïso, and Santiago.…”

“…1, Clark et al, 1990;Hawkes et al, 2002;Sillitoe, 2003;Chen et al, 2010b). Of these, the newly discovered Mina Justa Cu (-Ag) prospect is the largest Cu-rich IOCG mineralization (Table 1) with an indicated resource of 346.6 Mt at an average grade of 0.71 % Cu, ~ 3.8 g/t Ag and 0.03 g/t Au (Chen et al, 2010a). The IOCG deposits in northern Chile, mainly between latitudes 22° and 31°S ( Fig.…”

“…The principal IOCG deposits in northern Chile and southern Peru were mainly generated in Middle-Late Jurassic (165-155 Ma) and Early Cretaceous (120-100 Ma) epochs (Table 1; Sillitoe, 2003 and references therein;Chen et al, 2010a). The Middle-Late Jurassic deposits are located near the Pacific coast, west of the Early Cretaceous belt.…”

“…Most Precambrian IOCG deposits are believed to have been distributed in intracratonic settings, typically 100 to 200 km inland from cratonic margins, and appear to form during episodes of supercontinent breakup (Groves et al, 2010). In the case of the Central Andes, Mesozoic IOCG mineralization was associated with an active continental margin (Sillitoe, 2003;Chen et al, 2010a). The remelting of mafic crust generated by upwelling mantle was inferred in both Central Andean and Precambrian IOCG tectonic regimes Mesozoic Iron Oxide Copper-Gold Mineralization in the Central Andes and the Gondwana Supercontinent Breakup (Atherton et al, 1983;Pollard et al, 1998;Groves et al, 2010).…”