Ancient (>3.7 Ga) detrital zircons represent some of the few remaining relicts of Earth's earliest evolution. A metagreywacke from the northwestern margin of the Superior Province, Canada, has abundant Paleoarchean detrital zircon with peaks in age distribution at 3.86, 3.79, 3.74, and 3.32 Ga. A fuchsitic quartzite from the western margin of the Rae Province, Canada, contains entirely Paleoarchean detritus with peaks in age distribution at 3.86, 3.76, and 3.72 Ga. Both samples contain a small (2%–4%) proportion of zircon grains that are ≥3.9 Ga. Hf isotopic analysis indicates that a large proportion of the Paleoarchean zircon from both samples...