When stone recounts the past

Mingan Archipelago National Park Reserve

When stone recounts the past

Île St-Charles' Cliffs
Île St-Charles' Cliffs
© Parks Canada / M. Boulianne / O 01 38 09, 1988

The natural environment of the Mingan Archipelago has struck the imagination of visitors since it was first discovered. And, looking at the island beaches scattered with huge limestone monoliths that seem to have just stepped out from the sea, one can well understand why. Some exhibit their nudity bravely; others, more modestly draped in vegetation, conceal themselves in the islands' northern forests.

Here is how the famous botanist, Brother Marie-Victorin, described the Mingan Islands: " ...the Mingan Islands are daughters of the sea: they are fragments, pieces of an ancient land slowly deposited in the bottom of the oceans... " To understand the origins of the extraordinary Mingan landscape, we must go back in time to well before the dinosaurs.

Aerial view of Grosse île au Marteau
Grosse île au Marteau
© Parks Canada / É. Le Bel / A 02 136, 1996

The Formation of the Islands

The North Shore Canadian Shield survived an era of fire and volcanoes due to the extremely hard rock material of which it was composed. North Shore rock is estimated to be nearly one billion years old. When life developed on earth, the first marine organisms were generated in an ancient sea on the edge of the Canadian Shield. Major rivers were already criss-crossing the area and eroding the Shield, carrying rock particles to the sea. This sediment, combined with the remains of marine organisms, would slowly form a sea floor made up of limestone strata.

With the shifting of the earth's crust, this limestone bedrock emerged as a huge plateau. The friable mineral fell an easy victim to erosion, and the huge tableland was soon covered with splits and cracks. The rivers running down from the Canadian Shield used these natural corridors to reach the sea. And as they did so, they segmented the tableland, thus creating the Mingan Islands. Over time, nature eroded and sculpted the coastline of the islands into works of art.

This grey limestone, over 450 million years old, still conceals many secrets. Thanks to its origins in the very beginnings of life and its makeup of mineral and animal remains, it is a treasure-trove of fossils. This explains the major scientific importance of the archipelago.

The Monoliths

Île Niapiskau's Monoliths
Monoliths, île Niapiskau
© Parks Canada / P. Saint-Jacques / D 02 04 295, 1989

This story begins some 20,000 years ago during the last major ice age. With the gradual cooling of the earth, ice floes slowly spread over the whole of North America, including the Mingan Archipelago, which was covered by 2.5 km of ice. Because of the weight of the ice, the whole continent sank.

Later, the earth warmed up again and the glaciers began to melt. There were two consequences to the thaw: the remarkable rise in the ocean level, and the slow but gradual emergence of the continent. Indeed, 10,000 years ago, there were some 85 m of water over the archipelago.

After slowly rising for 2800 years, the tip of the islands broke the surface, and Nature began her slow process of erosion. The waves, the changing sea level and the winds, as well as seasonal freezing and thawing, caused the limestone to gradually crumble away. The first monoliths appeared.

The islands continued to rise from the water for many centuries, and the sea and the currents kept up their work on the new land mass. The continent is still rising today, and the erosion carries on. The monoliths, created from friable rock over 450 million years old, are prey to erosive agents which continue to sculpture and model them, bit by bit. These limestone sculptures pointing skywards in the island landscape form the largest group of monoliths in Canada.

But there are other points of interest on the archipelago, other great works of nature: grottoes, archways, strange silhouettes, fossils and cliffs also have their age-old stories to tell.

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