Two rocks — one dark, dense and magmatic, the other light-colored and granite — stood out from everything else scattered across the rocky slopes of the Pinerolo area and the Chisone Valley, in the heart of the Western Alps.

That was enough to pique the curiosity of researchers at the University of Turin: Rodolfo Carosi, Professor of Structural Geology and President of the Italian Geological Society; doctoral student Francesco De Cesari; and the rest of the University’s research team, including Chiara Montomoli, Salvatore Iaccarino and Davide Dana.

What followed was an unexpected discovery that is rewriting the history of the mountains: their origins do not date back 300 million years, as previously believed, but 530 million years — nearly twice as old.

Carosi and De Cesari have challenged the established interpretation of the region’s geological history, also revisiting an early geological map drawn in 1913. More than a century ago, no one could have imagined that the Alps had “grandmothers” far older than Pangea, the supercontinent that formed much later.

“These two specimens,” Carosi says, “change what we know about the orogeny of this region and the composition of its basement.

“The Alps as we know them today date back ‘only’ 40 million to 50 million years, when the European and African tectonic plates collided. Based on the specimens we had previously found, we knew there had been an earlier mountain range, known as the Variscan Mountains, dating to the Paleozoic Era.

“In the Pinerolo area, we have now encountered an even older generation: the Cadomian.”

For De Cesari, 28, who was born in Lucca and now lives in Turin, the discovery is doubly exciting. A researcher in the final year of his doctoral program, he chose geology because of his passion for nature and hiking at high elevations.

Researcher Francesco De Cesari conducting fieldwork

“I’ve always been fascinated by the idea of understanding how the landscapes I saw as a child were formed,” he says.

“Faced with those two rocks,” he adds, “we wanted to get to the bottom of it. So, we sent them to a laboratory in Bern, where another researcher originally from Turin, Daniela Rubatto, works. Thanks to the zircon crystals inside them, we were able to reconstruct the missing piece of the story.”

It is a chapter that takes us back more than half a billion years and requires considerable exercise in imagination.

It is the beginning of the Cambrian Period, when Earth had nothing resembling the forms of life we know today.

“The evidence available to us,” explains the President of the Italian Geological Society, “is limited to fossils of marine organisms, algae, pollen and other primitive forms of life. We would have had to wait another 300 million years or so for dinosaurs to appear. The first hominins, meanwhile, would not emerge for more than another 520 million years.”

Yet in this seemingly barren world, there was already a mountain range with features resembling those of the future Alps.

“We believe it stretched for thousands of kilometers,” De Cesari says, “with peaks roughly comparable to those we see today, between 5,000 and 6,000 meters high.”

And it was almost by chance that the discovery was made in the Chisone Valley, in an area assigned to the researchers by Ispra as part of a project to produce a new geological map of Italy.

“It’s the beginning of a journey,” De Cesari says. “Now we’ll have to study the characteristics of this Cadomian ridge.”

The Turin team’s discovery in the Chisone Valley was presented at the latest congress of the Italian Geological Society, held in Padua together with the Italian Society of Mineralogy and Petrology, and was published in the prestigious international scientific journal Terra Nova.

“It’s a finding,” Carosi says, “that allows us to reconstruct a still little-known chapter in the geological history of the Western Alps and of the ancient continent of Gondwana — which existed even before Pangea and to which these rocks belonged hundreds of millions of years before the opening of the Alpine Tethys Ocean and the final formation of ‘our’ Alps.”

— © ALL RIGHTS RESERVED.