Living Rock

A guest post by Marc St-Onge. Photo by Michelle Valberg.

Four billion years of Earth history—and not a day less.

From the Beaufort Sea to the south-eastern shores of Iceland, the Arctic’s geological past is not only remarkably rich and turbulent, but also unique on this planet. No other place on Earth can claim the full planetary rock record as documented in the Arctic, with the polar record including the oldest rocks in the world. These range in age between 3.8 and 4.03 billion years old; the Earth itself is only slightly older at 4.55 billion years. It’s a unique rock record that includes some of the earliest traces of life itself—specifically, circular plate-sized mounds called “stromatolites” formed by bacterial colonies of blue-green algae once living at the bottom of shallow, warm equatorial seas and now to be found, 2.9 billion years later, in the Canadian Arctic.

This unique geological record includes Earth’s first Himalayan-scale mountain belt with the ancient, now-eroded mountains that extended beneath Hudson Bay through northern Quebec and southern Baffin into western Greenland. These mountains formed 1.8 billion years ago when the Quebec-Ontario landmass collided with that shared by Nunavut, the Northwest Territories, and Greenland. The resulting ranges were similar in every way to the modern Himalayas in south-central Asia.

At the younger end of the geological spectrum, the unique Arctic record includes the most compelling evidence for what is known as the “Little Ice Age”, a period of long, cold winters and short, cool summers that characterized the climate of the northern hemisphere from the late fourteenth century to the end of the nineteenth. Inconveniently, the Little Ice Age was also the historical period when polar explorers ventured into Arctic Canada, beginning Sir Martin Frobisher (and continuing with Franklin, Ross, McClure, and many others). Geologically speaking, this was definitely a cast of not checking the weather prior to departure!

Four billion years of Earth history, full of violent volcanism and flooding that would have impressed Noah—there were several—colliding continents, wandering supercontinents … and yet, life persisted throughout, somehow. The record graven the Arctic’s living rock is a gripping tale open to those who learn its language, and read it closely. Like any truly great book, it leaves those who peruse it utterly awe-struck.


Marc is Senior Research Scientist and Head of Regional Geology at the Geological Survey of Canada, Natural Resources Canada. His passion for and knowledge of Arctic geology served as inspiration for a recent short story by Margaret Atwood (“Stone Mattress”), and his innovative work led to the publication of the “Geological Map of the Arctic” in 2011, the “Tectonic Map of Arctic Canada” in 2015, and the GSC’s first-ever geological maps in Inuktitut, also in 2015.

Leave a Reply

Your email address will not be published. Required fields are marked *