A comparison of Nd model ages and U–Pb zircon ages of Grenville granitoids: constraints on the evolution of the Laurentian margin from 1.5 to 1.0 Ga

Terra Nova, 24, 7–15, 2012 Abstract Concordance and discordance between Nd model ages and U–Pb ages is still widely misunderstood in the geological community. In the SW Grenville Province, plutonic orthogneisses often yield T DM ages significantly older than U–Pb crystallization ages, but this can be understood in a model where a series of crustal Nd isotope evolution lines departs at intervals from the depleted mantle (DM) evolution line. …