When walking along a South Shore beach, it is hard not to admire the brightly coloured pebbles. While some may take a closer look, many rarely consider how these rocks shape our lives. Processes that occurred sometimes over a billion years ago determine everything, from the curve of our coastlines, to the industries that make and break our economy, to whether our water is safe to drink.
Geologically, Nova Scotia is both diverse and unique, in part because it is the amalgamation of two ancient land masses. Over hundreds of thousands of years, these two land masses migrated across the globe and collided. While what is now the north of the province originally formed off the coast of Europe, the southern half originated off the coast of Africa.
Some of the most unique rocks of the South Shore are outside Lunenburg at Blue Rocks. The mesmerizing light and dark colour banding of the grey-blue rocks results from layers of crushed marine shells. If you look closely, you can even see ancient ripple marks from the action of water on the sediment-turned-rock.
The very existence of Mahone Bay also comes down to the dance between rock and water. The limestone and gypsum that underlie this region are easily eroded. This erosion caused the divot that is Mahone Bay, which was later flooded as sea levels rose after the last glaciation. This same glaciation also led to the drumlins, elongated hills formed beneath a glacier, that now pepper the land around Mahone Bay and Chester.
Another geological marvel and tourism hotspot is Peggy’s Cove. Its massive granite rocks formed when molten magma cooled and crystallized several kilometres beneath the earth’s crust, only to be later exposed through erosion. Glaciers that covered the entire continent advanced and retreated, polishing the stone smooth and leaving behind unique striations. Many parts of the coastline were carved by these icy giants.
It is this same granite that sometimes houses one of our most volatile elements – uranium. Like gold, which often occurs in veins of quartz, uranium ore only develops under specific conditions. Here, uranium is found in igneous rock, like the granite that stretches from Peggy’s Cove inland towards the Annapolis Valley. While gold is frequently found alongside arsenic, uranium is typically found alongside radon, a radioactive gas also known for its harmful effects on human health.
So next time you’re admiring pebbles along the seashore, remember those pebbles are subtle evidence of the ancient geological processes that still shape our lives today.
Learn more about Nova Scotia’s geology at https://atlanticgeosciencesociety.ca/
Lia Robles Gil is a science communicator who has lived all over Canada, but currently resides in Lunenburg. You can find them on Instagram and Bluesky @liaroblesgil
