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 °C to <350 °C using diffusion profiles of Ti and δ¹⁸O 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 °C to δ¹⁸O = 10.7‰. We use diffusion modeling to reproduce the observed Ti and δ¹⁸O profiles, which provides lifespan estimates at Haquira of 75–170 k.y. for the period from initial magma and fluid injection at 700 °C to cooling below 350 °C. The bulk of the Cu-Mo-Au ore formed in ≤35 k.y., indicating that large-scale, economic porphyry copper deposits can form rapidly.