Mechanisms of continental growth in extensional arcs: An example from the Andean plate-boundary zone

During the Late Triassic, Jurassic, and Early Cretaceous, an extensional magmatic arc was formed in the Andean margin of northern Chile. Plutons emplaced at ramps within a hinterland-propagating extensional duplex were fed by dikes that transferred magma through the lower crust from a reservoir in the mantle Phases of volcanism separated phases of plutonism, and our model demonstrates that plutonism was favored only when upper-plate extensional fault systems were active. When they were not, dikes cut across inactive faults, and magma rose directly to the surface during volcanic phases of arc growth.