By Sarah Sloat
Around 180 million years ago, Earth fundamentally changed when Gondwana began to dismember. Today, present-day places, including South America and Australia, are visible chunks of this former ancient supercontinent, as well as not-so visible slices of land, like the submerged Zealandia — debatably Earth’s eighth continent.
However, scattered from Spain towards Iran, are signs of another lost continent — a once-Greenland sized relic called Greater Adria. Recently, in the journal Gondwana Research, geologists published the most detailed look at Greater Adria’s demise yet, in turn explaining how it went from being part of a supercontinent to being buried beneath Europe.
A team led by Professor Douwe van Hinsberg from Utrecht University spent the past decade collecting and examining geological data from parts of southern Europe, Africa, and western Asia, looking for evidence of Greater Adria. They took specific note of the orientation of minuscule magnetic minerals, which were formed by primeval bacteria.
Hinsberg explained to Live Science that bacteria make the magnetic particles in order to orient themselves to Earth’s magnetic field. When mineral-filled sediment turns into rocks, that orientation is frozen in time. In turn, this team’s examination revealed that the rocks had undergone extremely large rotations — evidenced by fault lines that look “like pieces of a broken plate.”
With this knowledge — and GPlates, software that enabled the team to create how Earth’s tectonic plates have moved over time — the team extrapolated that Greater Adria broke away from Gondwana around 240 million years ago. From there, it began to drift northward, collecting mineral-filled sediments. Between 100 million and 120 million years ago, it collided with what’s now Europe.
In that destruction, it’s likely that a fraction of the ancient formation was scraped off — and today those scraps exist as rocks found in places like Turin, Italy, and Croatia’s Istria region. It’s also likely that this collision served as the foundation for the formation of a handful of southern Europe’s mountains. At speeds of no more than 3 to 4 centimeters per year, the ancient continent drove into Europe, shattering its crust, and driving the majority of it within Earth’s mantle.
Understanding Greater Adria is a puzzle that’s been ten years in the making, and things aren’t completely settled yet. Even what to name the ancient landmass has been debated. But its known existence is a sign that undiscovered history can still be found in unexpected places, and a reminder that while our own continents may seem settled, our own landmasses are still moving today.
(For the source of this, and many other quite interesting articles, please visit: https://www.inverse.com/article/59206-greater-adria-continent-europe-collision/)