One of the oldest geological mysteries of the Atlantic Ocean may finally be solved.
Scientists say they have discovered why Bermuda - a small group of islands in the middle of the North Atlantic - continues to stand on the surface, even though its volcanoes have been extinct for more than 30 million years.
A team of researchers from the Carnegie Institution for Science and Yale University discovered that beneath Bermuda lies a massive rock structure, formed after recent volcanic eruptions, that has kept the island "suspended" above the water since prehistoric times.
For decades, scientists had been faced with a paradox: Usually, volcanic islands in the ocean need constant heat activity from deep within the Earth to keep them from gradually sinking. But Bermuda remained an unexplained exception.
Now, researchers have identified a giant rocky structure, about 19 kilometers thick – roughly the length of Manhattan Island in New York City – located beneath the normal oceanic layer.
This rock is lighter than the surrounding material and functions as a giant floating platform, keeping the entire area elevated.
According to researchers, this layer was created 30 to 35 million years ago, when hot magma from deep within the Earth rose to the surface, spread beneath the oceanic crust, and then cooled and solidified.
To reach this conclusion, scientists did not conduct new drilling.
They analyzed more than 20 years of seismic data from natural earthquake tremors, recorded by a single monitoring station on the island.
By tracking how seismic waves changed speed in different rock layers, the team was able to create a "map" of the structure up to over 40 kilometers below the surface.
But the discovery could also have implications for another famous mystery: the so-called "Bermuda Triangle."
Researchers point out that the area has natural gravitational and magnetic anomalies.
In some parts, gravity is slightly weaker than usual due to lighter underground rocks, while rocks rich in iron and titanium can cause stronger magnetic signals that affect compasses and navigation devices - although experts stress that these are completely natural and harmless phenomena.
"Bermuda is an exciting place to study because many of its features do not fit classical geological models," said researcher William Frazer. "This suggests that there are processes in the Earth's mantle that we do not yet fully understand."