For years, scientists have tried to understand why Bermuda sits much higher than the surrounding Atlantic Ocean floor despite having no active volcanoes for millions of years. Now, a new study by American researchers claims to have found the answer hidden deep beneath the island.
The findings, published in the journal Geophysical Research Letters, suggest that Bermuda is sitting on a rare underground rock structure unlike anything usually seen beneath volcanic islands. The research was led by William Frazer, a seismologist at Carnegie Science, and Jeffrey Park of Yale University.
Scientists Study What Lies Below
According to the Carnegie Institution for Science, most volcanic islands like Hawaii are formed above what scientists call a mantle plume. This is a column of very hot
rock rising from deep inside Earth’s mantle. As the hot material pushes upward, it creates volcanoes and lifts the seafloor.
Over time, when volcanic activity stops and tectonic plates move away, these raised areas usually sink back down. But Bermuda did not follow that pattern.
Even after its volcanoes became inactive more than 30 million years ago, Bermuda still remains around 1,600 feet higher than the nearby ocean floor. This unusual feature left scientists puzzled for decades.
To understand why, Frazer and Park studied seismic waves created by large earthquakes across the world. These waves move differently depending on the material they pass through inside Earth. By studying recordings from a seismic station located on Bermuda, the researchers created a detailed picture of the underground structure beneath the island, down to nearly 20 miles deep.
A Thick Rock Layer Was Found
The team discovered something unexpected beneath Bermuda, a huge rock layer more than 12 miles thick sitting below the oceanic crust.
Unlike the surrounding mantle rock, this layer is lighter and less dense. Because of this, scientists believe it acts almost like a floating platform that helps keep Bermuda and the nearby seafloor raised.
Researchers said this structure is known as “underplating.” They believe it formed during Bermuda’s volcanic period millions of years ago when carbon-rich molten rock entered the bottom of the crust and later cooled there permanently.
The study also suggests that this material may have originally formed hundreds of millions of years ago during the creation of the ancient supercontinent Pangea.
Frazer explained why the discovery is important. “Bermuda is an exciting place to study because a variety of its geologic features do not fit the model of a mantle plume, the classic way for deep material to be brought to the surface,” he said, as per the Carnegie Institution for Science.
“We observe thick underplating, something that is not observed at most mantle plumes. Combined with recent geochemical observations, this suggests that there are other convective processes within Earth’s mantle that have yet to be well understood.”
Researchers Continue Further Search
The discovery has now opened up new questions for scientists studying Earth’s interior.
Frazer is currently searching for similar underground structures beneath other islands around the world to find out whether Bermuda is unique or whether there may be many more islands formed in a similar way.
The findings have been published in the scientific journal Geophysical Research Letters, while details of the research were also shared by the Carnegie Institution for Science.






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