The significance of Nd isotope mapping in Precambrian orogenic belts: A case study from the Saguenay region of the Quebec Grenville Province

Fifty new Nd isotope analyses are presented for the Saguenay region of the Quebec Grenville Province. Most samples yield juvenile Pinwarian model ages, with an average depleted mantle model age (TDM) of 1.55 Ga, typical of the Quebecia accreted arc terrane. However, ten samples yield older model ages, averaging 1.78 Ga. These samples have an approximately linear geographical distribution, and are interpreted as melts of old basement panels …