Geology of Brier Island

Brier Island rock

The Brier Island area owes its unique geological features to ancient lava flows of molten basalt. Straight-sided rock columns (like the famous Balancing Rock) are prevalent across the shoreline of Brier Island & Long Island, making the coast a sight to remember.

In the Beginning…

Lava erupted from the rifts between continental plates, helping form the Atlantic Ocean (about 200 million years ago, slightly before we were born).

Those lava flows created a mountain range called the North Mountain Basalt Ridge. Today this mountain ridge is mostly underwater, and the parts above water make up a majority of Nova Scotia’s Bay of Fundy shoreline. But why do the rocks on Brier Island look so different?

Brier Island Rock Columns

Ridge Rocks on Brier Island

The straight-sided, vertical columns of basalt on Brier Island might look more like sculptures than natural rock formations, but they were created by nature. Brier Island’s rock columns formed as the surface of a hot lava flow started to cool.

The ancient lava flow that made the rock columns cooled – and shrank – at an even rate, pulling apart in polygonal patterns. This even cooling and shrinking started at the surface, and continued deeper into the lava flow. Molten rock turned to solid rock, eventually creating the columnar joints you can see today.

On LongBalancing Rock Hike on Long Island Island, you can hike out to a famous rock column called Balancing Rock – a 9m / 30ft free-standing pillar. It isn’t hard to imagine how Balancing Rock got its name!

On Brier Island you can view vertical rock columns along the Grand Passage shore (between Brier Island and Long Island), and at the Ridge Rocks all the way out to Gull Rock. Brier Island’s rock columns are most exposed (and best viewed) at low tide.

Hunting for Rocky Treasure

Pea Jack Cove rocks on Brier Island

Rockhounding is popular on Brier Island where persistent (and lucky) mineral collectors can find amethyst, agate, jasper, calcite, and zeolites formed inside rounded stones. How did these minerals get inside the stones?

Remember our 200 million year old lava flows? Well, when the lava hardened and trapped gas vapours forming bubbles. When the gas leaked out it left cavities that filled with mineral-rich solutions which hardened into minerals.

The cavities in the rock where minerals form are called “amygdules”, and can be either round or oval, depending on whether or not the lava was still moving when they were created. A rock is more difficult to crack than an egg, but if that rock hides an amygdule, you just found your own unique souvenir.

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