New evidence for ~Â 4.45Â Ga terrestrial crust from zircon xenocrysts in Ordovician ignimbrite in the North Qinling Orogenic Belt, China

► Cores to > 3.9 Ga zircon xenocrysts have Hf model ages extending back to 4.45 Ga. ► These provide the second known example of earliest generation of crust on Earth. ► Zircon rim ages of ~ 3.7 Ga attest to ancient reworking of Hadean source rocks.