“Forget Atlantis. Without realizing it, vast numbers of tourists spend their holiday each year on the lost continent of Greater Adria,” declared Douwe van Hinsbergen, professor of global tectonics and paleogeography at Utrecht University, in a CNN press release. Such sensational claim is no hype: under the scenic ridges of the Alps, the majestic Apennines, and the undulating mountain ranges of Greece and Turkey, lies concealed the bruised and battered remnants of a lost continent of the size of Greenland that formed an integral part of Southern European geology.
The existence of Greater Adria started almost 240 million years ago, when it broke away from the supercontinent Gondwana and drifted north into ancient Tethys Ocean. It was an inundated continent with only a few islands rising out of shallow tropical seas a situation similar to that of modern Zealandia, a new National Geographic analysis suggests.
The real drama played out 100 to 140 million years ago, when Greater Adria ran into the southern margin of Europe. Unlike the fairly simple tectonic interactions that formed the Himalayas, the Mediterranean is, in van Hinsbergen’s words to LiveScience, “quite simply a geological mess.” Plates here are not just crashing into each other; they are being bent, broken, and stacked up in a confusing collection of faults and folds. The impact didn’t just squash Greater Adria, it shattered it. The top of the continent was stripped away, like the skin on a giant apple, and added to the atop-moving European plates as the raw material of the Alps, the Apennines, the Balkans, and the mountains of Turkey and Greece.
The mechanism, subduction, is the principal force behind orogeny mountain building where one tectonic plate is pushed beneath another. When the 100-kilometer-thick Greater Adria crust was pushed beneath Southern Europe, it was consumed into the mantle, leaving only isolated surface outcrops of limestones and seashells today. These ancient sea rocks, which had lain silent and still for millennia, were thrust up by tectonic violence, now constituting the picturesque countryside cherished by hikers and geologists.
Beyond fieldwork, reconstructing this lost continent took. The Utrecht team, led by van Hinsbergen, took over a decade collecting geological and geophysical data from across more than 30 countries, which had their own conventions for mapping and geological histories. The achievement was facilitated by applying advanced plate reconstruction software, namely GPlates, where the scientists were able to see the complicated, time-lapse record of the Mediterranean tectonic plates in unprecedented high resolution (Science.org). The seismic tomography integration imaged deep Earth structures from seismic waves the researchers followed the deformed remnants of Greater Adria’s crust to depths of up to 1,500 kilometers below the Earth’s surface.
Seismic tomography has been very helpful in charting these remnants of ancient continents. Because seismic waves move at varying velocities through varying forms of rock, researchers can trace chunks of subducted crust in the depths of the mantle. With the Greater Adria, such seismic “ghosts” ensure tectonic remnants jigsaw puzzle not only support Europe’s mountain chains but also provide for keys to the region’s active seismicity and volcanism. As van Hinsbergen continued to describe in the Gondwana Research journal, “Our research provided a large number of insights, also about volcanism and earthquakes, that we are already applying elsewhere.”
Its significance to earth science is deep. By correlating the volume of residues constructed by mountains with the subducted plate size, geologists can reconstruct the tectonic past with ever-growing accuracy. This method not only reveals where mineral deposits are generated and the pattern of seismic hazard, but also how continents are created, disintegrate, and sometimes disappear nearly completely from the earth’s surface.
Greater Adria’s tale is one of praise for modern geoscience’s resilience: from precise gathering of rock samples and paleomagnetic data to use of high-technology computer codes and seismic imaging, researchers have reconstructed an epic of collapse and re-birth that continues to mold the Mediterranean scenery. Its legacy extends, not merely in the rocks at our feet but in the very mountains sculpting Southern Europe’s scenery and seismological nature.
