The Grenville Province represents a complex, highly metamorphosed orogenic belt at the southeastern margin of the Canadian Shield that is composed of different lithotectonic domains of various ages that have all been affected by the 1.0 Ga Grenville Orogeny. The present study focuses on one of the youngest regions, the Quebecia terrane, and through reconnaissance neodymium isotope mapping, investigates the extent of an old crustal block that predates the Grenville Orogeny. The Quebecia Terrane is found within Central Quebec and is a Mesoproterozoic arc terrane that was constructed around 1.5 Ga. Utilizing the Samarium-Neodymium dating method, previous research had identified a few isolated neodymium signatures of older crustal ages, and through reconnaissance mapping, several of these Paleoproterozoic crustal blocks are suggested to represent a single fragmented crustal panel. The study focused on more detailed mapping of these blocks in the areas of Baie Comeau, Forestville, Labrieville and Pipmuacan in Central Quebec. The full extent and connection between the fragments has been mapped as a series of Paleoproterozoic crustal blocks extending longitudinally through the Quebecia terrane. These blocks are embedded within the younger terrane, suggesting that the old panel was incorporated sometime during the accretion of Quebecia to Laurentia. It is possible that the old panel broke off from older Laurentian crust and reattached during the accretion of the Quebecia terrane via strike slip tectonics, implying that the Quebecia terrane itself consists of more than one accreted unit. The present study found that the older neodymium isotope signatures were consistent with the Berthe Terrane in the Manicouagan region to the north, providing evidence for the origin of the older panel within Quebecia. However, by invoking a division of Quebecia into a north and south segment, this implies a Composite Arc Belt model for the Central Grenville Province. / Thesis / Master of Science (MSc)