Latest Cretaceous-early Paleogene “boom” of porphyry Cu mineralization associated with the Laramide magmatic arc of Mexico

© 2016 Elsevier B.V. Porphyry copper and associated deposits are widespread through most northwestern Mexico, particularly in Sonora and Sinaloa, in the northwestern part of the country. These deposits belong to a NW-SE trending copper belt that extends from southwestern USA to southern Mexico. The copper mineralization is clearly linked to subduction-related calc-alkaline plutons formed during the eastward migration of the Cordilleran magmatic arc, largely coincident in time and space with the Laramide Orogeny (80–40 Ma). The economically most important porphyry copper deposits were emplaced in the southwest margin of the North American craton. The porphyry copper mineralization was formed during the latest Cretaceous to early Paleogene, between ~ 75 and 52.4 Ma, but it was particularly fertile between ~ 69 and 54 Ma, when the larger copper concentrations were deposited to form the famous copper cluster of Arizona, New Mexico and Sonora. During this time, more than half of the total porphyry copper-related metals of the entire Cordillera was deposited. This large copper accumulation developed south of the classical flat-slab Laramide province, characterized by uplift of large crustal blocks and mostly amagmatic conditions. An inferred slab tear zone separated this zone from a slab segment, above which, asthenospheric magma flux favored copper concentration. The Mexican porphyry copper belt accounts for ~ 30 deposits, out of which, the Buenavista del Cobre (~ 30 Mt Cu) and the La Caridad (~ 8 Mt Cu) are the most relevant. More to the south, close to the boundary between Sonora and Sinaloa, the porphyry copper deposits are smaller (< 1 Mt Cu), usually containing gold as a locally important commodity. This fact is coincident with the ending of the North American cratonic crust, and the beginning of a basement dominated by a more primitive crust, characterized by the Late Jurassic-Early Cretaceous Guerrero island arc terrane.