The southern limit of Archean crust and significance of rocks with Paleoproterozoic model ages: Nd model age mapping in the Grenville Province of western Quebec

Detailed Nd model age mapping in the Grenville Province of western Quebec has identified biotite gneisses with crustal formation age intervals of 2.5-2.9 Ga and 1.8-2.0 Ga. Although the presence of Archean crust in the Grenville Parautochthonous Belt has been known for some time, the results of Nd model age mapping, combined with geochemical and aeromagnetic data, indicate that the Archean parautochthon extends more than 20 km to the south of …