How do Newfoundland island and Labrador differ in their geology?

Newfoundland island and Labrador are distinct physiographic regions with fundamentally different geological origins.1

Newfoundland Island
The island is part of the Appalachian geologic province of North America. Its complex structure was shaped by continental drift, volcanic activity, and crustal deformation. Geologically, it features ancient rocks of Europe and Africa on the east, newer Appalachian rocks on the west, and the remnants of an ancient ocean floor trapped between them. Significant mountain-building events, such as the Avalonian orogeny and the Acadian orogeny, played key roles in shaping the island's terrain.123

Labrador
In contrast, Labrador is geologically part of the Canadian Shield, which contains some of the oldest rocks on Earth. It is primarily composed of Precambrian igneous and metamorphic formations. While the interior is characterized by a saucer-like plateau, the region also includes the Labrador trough, which holds extensive iron-ore deposits, and the rugged Torngat Mountains in the north, formed by ancient tectonic collisions.14