Why the cliffs exist

If it were not for the sweeping cliffs at Joggins, we would not know of the fossil record preserved, nor would it have played a pivotal role in the history of science. The Joggins cliffs exist because of the last Ice Age and the extreme tides of the Bay of Fundy.

Panorama of the cliffs (Andrew MacRae photograph)
Panorama of the Pennsylvanian rocks and Quaternary glacial till overlying the ancient wave-cut platform (Andrew MacRae photograph)

During the most recent period of Earth's history, the Quaternary, a continental ice cap covered most of Canada, including Nova Scotia. The ice cover melted about 10,500 years ago. In geological terms, the ice cover vanished quickly and the Earth’s crust rebounded upward with the release of the weight (like a foam cushion rebounds after you depress it with your hand). As the crust rose, the former shoreline rose as well, becoming stranded high above the present day shoreline. The ancient shore forms the flat surface at the top of the rock cliffs. Overlaying this surface is a thick layer of clay (glacial till), which washes down over the rocks and paints them brick red.

…the action of the tides of the Bay of Fundy being so destructive as continually to undermine and sweep away the whole face of the cliffs, so that a new crop of fossils is laid open to view every three or four years.
Sir Charles Lyell, Travels in America (1845) p. 187

Every 6½ hours, the powerful Fundy tides flood the Bay and then withdraw. The waves pound the cliffs relentlessly during the highest tides. Each rock brings with it the possibility of revealing a pressing of fossil life from the pages of this marvellous chapter of the big volume.

Tide at Joggins, Nova Scotia

Published: 2016-05-02