Rapid formation of porphyry copper deposits evidenced by diffusion of oxygen and titanium in quartz

The lifespan of magmatic-hydrothermal activity that results in large and economically viable porphyry copper deposits remains poorly described. Here, we estimate the duration of the magmatic-hydrothermal fluid flow at 700 degrees C to <350 degrees C using diffusion profiles of Ti and delta (super 18) O in quartz from Fe, Cu, and Mo sulfide-bearing hydrothermal veins and porphyry dikes at the Haquira East porphyry copper deposit, Peru. In situ measurements indicate all vein quartz is zoned in Ti (1-120 ppm), whereas high-temperature quartz has been re-equilibrated at 450 degrees C to delta (super 18) O = 10.7 ppm. We use diffusion modeling to reproduce the observed Ti and delta (super 18) O profiles, which provides lifespan estimates at Haquira of 75-170 k.y. for the period from initial magma and fluid injection at 700 degrees C to cooling below 350 degrees C. The bulk of the Cu-Mo-Au ore formed in < or =35 k.y., indicating that large-scale, economic porphyry copper deposits can form rapidly.