The landscape of Newfoundland and Labrador has had a remarkable geological history, formed over many millions of years by continental collision, mountain-building, volcanoes, oceans, rivers and ice sheets. The physical environment that has developed as a result is itself an important part of the region's heritage.
The Strait of Belle Isle divides the province into its two geographical components, Labrador and the island of Newfoundland, and closely approximates a division of great geological significance. Labrador is the easternmost part of the Canadian Shield, a vast area made up mostly of plutonic and metamorphic rocks, some of which are the oldest known on Earth.
Newfoundland represents the northeasternmost extension of the Appalachian mountain system in North America, and is much younger than Labrador. It formed from parts of three areas of the world brought together about 400 million years ago by continental drift - the constant movement of lithospheric plates on the Earth's surface. Central Newfoundland is the remains of an ocean floor that lay between North America and Africa about 500 million years ago. The island's west coast is part of the ancient margin of North America. The east coast was once part of southwestern Europe or North Africa. When the continental plates again separated (which led to the formation of the Atlantic Ocean basin) the split occurred east of where they had collided and this left a piece of the eastern plate attached to North America.
The last 200 million years of Earth history in Newfoundland and Labrador have been dominated by erosion. For most of that time, rivers stripped rock from the land surface, carrying it to the oceans to be deposited offshore. Long periods of fluvial erosion led to the development of extensive plains, the remnants of which are the upland surfaces of the province.
For the last 2 million years, during the Ice Age, great ice sheets advanced and retreated across Newfoundland and Labrador many times. At the last glacial maximum, 18,000 years ago, the Laurentide Ice Sheet covered most of Canada including Labrador. The tip of the Northern Peninsula was the only part of Newfoundland overrun by the Laurentide Ice Sheet; the rest of the island was covered by its own independent ice cap which originated on uplands and spread out towards the coast.
Glaciers had an enormous effect on the landscape, smoothing and polishing wide areas, eroding lake basins, and carving deep valleys through mountains. Along the coast, these valleys were later flooded by the sea, creating deep fjords.
As climate warmed, the ice retreated inland, leaving behind a more subdued landscape, in places covered by till or gravel washed out of the melting glaciers.
Sea level around the coast of Newfoundland and Labrador changed considerably as a result of the last glaciation. Ice sheets of great weight pushed land areas downward, and squeezed them outwards beyond the ice margin. As the ice melted, the land rebounded, and material which had been displaced gradually returned to its original position. Evidence of this process can be seen in most areas of the province. Beaches, deltas, and the remains of marine fauna can be found tens to hundreds of metres above the present level.
The coast of Labrador continues to rise as the land rebounds, but much of the Newfoundland coast is sinking as displaced material is returned and the land settles. Submerged shorelines, inland migration of beaches and drowned forests are common indicators of this rising sea level around the coast.