500 Myrs in the making: control of Gondwana margin assembly on Carboniferous orogenic gold in Peru

Carboniferous intrusion-related orogenic gold deposits in the Eastern Andean Cordillera display a high distribution-density in northern Peru. New geological structural mapping suggests a basement domain boundary controlling the emplacement of large plutonic complexes and associated hydrothermal gold deposits. The southern Montanitas Domain basement comprises thrust nappes of imbricated ophiolite slices and granitic gneiss. The basement of the northern Pataz Domain forms a fold-and-thrust belt, where low-grade Ordovician volcanic arc rocks and marginal sedimentary rocks are thrust over semi-pelitic schists. Structural data indicates that both domains were deformed during a common orogeny, ascribed to the Late Famatinian (ca. 440 Ma) that affected the Eastern Cordillera to the south. North of the study area, no Late Famatinian imprints are documented. It is proposed that the study area is situated at the northernmost extent of an orogenic belt that formed through re-collision with the putative Paracas terrane that detached from Amazonia during Rodinia break-up. Carboniferous compression was accommodated in dextral strike-slip along the trans-crustal Rio Maranon Fault. We suggest that the greater width of the basement orogen to the south led to magma and fluid channeling at its northern tip. Gold mineralization focused in a narrow, strike-slip-induced dilation zone north of the basement block.