NEW BRUNSWICK

The geological history of the Hopewell Rocks in New Brunswick begins millions of years ago when the province was located near the equator. The rocks of New Brunswick are part of the Appalachian Orogeny, an ancient mountain range stretching from Newfoundland to Florida.

360 million years ago, the mountain building cycle was over, and erosion processes dominated. Water and wind use all mountains, as well as large volumes of gravel, sand and clay.

Near the high ground, flash floods washed down the valleys and canyons, washing away large masses of eroded sediment and depositing it in the form of gravelly debris. Further from the high ground, the sediments form alluvial plains with sorted layers of sand and clay.

The region covered by these terrestrial sediments in Atlantic Canada is called the Maritime basin (map of New Brunswick inserted in the geological map). Over time, the gravel, sand, and clay hardened and became conglomerates, sandstones, and shales. Because these deposits were formed near the equator, the climate was hot and dry.

Minerals containing iron oxidized, and the rocks turned into red formations (redbeds). Within these cycles of land sedimentation, shallow seas invaded southeastern New Brunswick. Limestone deposits, and evaporites, such as gypsum, potash, and salt rushed from the sea.

When the seas last receded about 330 million years ago, earth’s cycles of sedimentation began at again, covering the limestones and evaporites of younger sediments.

The landscape of the Hopewell Rocks offers vivid examples of marine limestone deposits and evaporites, and younger terrestrial red formations.

Marine erosion spurs and cliffs of conglomerate and tidal red sandstone are from the Hopewell Cape Formation. They represent coarse deposits of alluvial alluvial fans. Each erosion spur lasts only between 100 and 250 years before collapsing in the Bay of Fundy.

At the end of the southernmost beach, rocks of the Hopewell Cape Formation overlie limestone of the Lime-Kiln Brook Formation. Limestones contain fossilized stromatolites.

These cabbage-head-shaped structures were formed by layers of primitive algae in a marine coastal environment.