Zircon as a Monitor of Crustal Growth

Zircon has long played a key role in crustal evolution studies as the preeminent U–Pb geochronometer. Recent advances in analytical capabilities now permit investigations of complex grains at high spatial resolution, where the goal is to link zircon ages to other petrographic and geochemical information. Zircon can provide time-stamped ‘snapshots’ of hafnium and oxygen isotope signatures of magmas throughout Earth’s history, even at the scale of individual growth zones within a single grain. This information is an invaluable help to geochemists trying to distinguish magmatic events that added new, mantle-derived material to the continental crust from those that merely recycled existing crust.