Douwe van Hinsbergen, a geologist at Utrecht University in the Netherlands, has been exploring one of the most dramatic of these lost continents — known as Greater Adria. In a paper published in early September in the journal Gondwana Research, he and his colleagues studied rocks around and beneath the Mediterranean Sea to reveal the full extent of Greater Adria for the first time. “It’s enormous! About the size and rough shape as Greenland,” he says. You've never heard of Greater Adria? You're not alone.
The reason you've never seen it on a map or met anyone who's ever vacationed there is because it completely buried. And I don't mean under the sea. No, I mean Greater Adria is buried beneath southern Europe! A land under a land. How did that happen? Read on.
"About 140 million years ago, the two continents began to collide. Greater Adria got bulldozed and buried in the process and mostly sank beneath what is now Italy, Greece and the Baltics." And Greater Adria isn't unique, either.
Emerging studies of the Earth's mantle show likely traces of past lost continents. "Analysis of ancient rocks suggest that almost all of Earth’s earliest continents might have disappeared, taking with them much of the history of life on this planet. The evidence of how life first appeared may be lost somewhere down there in the depths."
The good news, however, is that lost continents are not entirely lost. They leave traces behind, if you know how to look for them. And just as Sherlock Holmes followed clues that others missed to solve the case, so do some of the world's greatest "sleuthing" geologists follow clues to help us better understand the world we live on. "Van Hinsbergen notes that rocks from Greater Adria got scraped off and incorporated onto the Alps, while whole chunks got embedded in southern Italy and Croatia. Even the parts of Greater Adria that got shoved dozens of miles down into the mantle, the layer below the crust, continue to influence modern Europe."
Under tremendous heat and pressure and over tens of millions of years, limestone rocks from Greater Adria turned into marble. Friction between Greater Adria and Europe then pulled the sunken rocks back to the surface, where people found them and mined them. “That’s where the marble came from that the Romans and the Greeks used for their temples,” van Hinsbergen says. As it turns out, Plato was standing on a real Atlantis, only he never knew it!
Greater Adria long remained unknown because it has been almost completely obliterated and obscured. But at least one other lost continent has been hiding in plain sight. "Maps of the ocean floor show a vast elevated region surrounding the islands of New Zealand, a formation known as Zealandia. Two years ago, a team led by geologists Nick Mortimer of GNS Science, a geological research company, and Rupert Sutherland of Victoria University Wellington, both in New Zealand, combined those maps with measurements of surface gravity and analysis of seafloor samples to show that Zealandia is much more than a bump in the ocean: It’s a single, continuous continent, the eighth in the world (or the seventh, if you lump together Europe and Asia as Eurasia), about two-thirds the size of Australia and more than twice as large as Greater Adria."
Scientists and researchers believe that a few million years ago, during the time of the dinosaurs, it made up a large part of the supercontinent called Gondwana. I don't know about you, but that is a name I'm not familiar with. "“Then it got separated 85 million to 100 million years ago,” says Rupert Sutherland, a New Zealand geological researcher. “It got stretched and thinned, resulting in a lower elevation, and it was also affected by the development of the 'Pacific Ring of Fire,' a zone of volcanic activity that rims the Pacific Ocean." If we were able to look at maps of the ocean floor, we'd see that Zealandia is much more than a bump on the ocean floor: It’s a single, continuous continent, the eighth in the world (or the seventh, if you lump together Europe and Asia as Eurasia), about two-thirds the size of Australia and more than twice as large as Greater Adria.
According to geophysicist Derrick Hasterok of the University of Adelaide, it now seems that Zealandia and Greater Adria are just two recent examples of what was once a regular Atlantis-like process. Continents were not always stable fixtures of our planet. So what caused all this instability? It is believed to be the result of radioactivity. The Earth was born with a lot more radioactive elements than it has now and much of them have since decayed away. The only way we know they ever existed is by the curious lack of high-radioactivity rocks in the modern continents. Those rocks don’t exist, because the continents in which they lived are long gone. Isn't science amazing?
Nobody will ever know what kinds of events took place on these lost continents. But it's important to learn as much as we can about the lost continents and to find out if there are more than these two that we're not currently aware of. Finding our past could help improve our future. "Just as Greater Adria pulled marble up to the surface in Europe, other continental collisions have excavated precious ores and minerals." It is hoped that this exploration will lead to the discovery of new deposits. “The world needs more copper and rare-earth elements for the green revolution. This could help us find them.”
I know this was a long blog today but I found it so fascinating that I wanted to share all the relevant details with you. It's extraordinary that after millions of years, we're still learning so much about the planet that we all call home.
Please join me back here tomorrow for what will be a far shorter blog, I promise! And for those of you who stuck those one out to the end, you have my deepest gratitude. I hope that you found it worthy of your time.