The Sesia Supervolcano

In the heart of the Western Alps, in Valsesia and Valsessera, lies the fossilised remains of an inverted supervolcano, whose roots are visible here. The discovery is credited to Silvano Sinigoi and James Quick, two researchers from the Universities of Trieste and Dallas who have been studying the geology of these valleys for over thirty years.

The story began around 300 million years ago, when the Earth consisted of a single, enormous continent dotted with numerous volcanoes. After around ten million years of eruptions, in what would later become the Valsesia region, a veritable catastrophe struck: a super-eruption caused the volcanic area to collapse, forming a caldera at least 15 km in diameter – the supervolcano. More than 500^km³ of pyroclastic material, fiery clouds and ash were hurled into the air, altering the landscape and affecting the climate. Then it all came to a halt. Around 100 million years ago, Africa broke away from South America, beginning its drift, and subsequently collided with Europe. As a result of this pressure, around 30 million years ago, the Alps were formed and, in the area comprising Valsesia, the entire Earth’s crust was folded, causing its deepest parts to rise along the Insubric Line, revealing the entire feeding system of the now-fossilised supervolcano.

Thanks to this process, we can now observe what used to be the Earth’s crust beneath the volcano, down to a depth of around 25 kilometres: this can be seen whilst driving through the Valsesia valley, from Balmuccia to the Gattinara area, stopping at the designated ‘geostops’ equipped with information panels. A situation that is unique in the world.

Link:Supervolcano