Hf and Nd isotopes in Early Ordovician to Early Carboniferous granites as monitors of crustal growth in the Proto-Andean margin of Gondwana

► Granitoids of the Sierras Pampeanas are dated as Ordovician, Devonian, and Carboniferous. ► In situ Hf isotopes on dated zircon and Sm-Nd whole-rock isotope data are reported for these granitoids. ► The proto-Andean margin was shaped largely by reworking of old crustal rocks.