Scientists Detect Unusually Buoyant Rock Layer Beneath Bermuda 30 Million Years After Volcanism Ceased

Researchers at the Carnegie Institution of Washington and Yale University have identified a concealed geological formation beneath Bermuda that has kept the Atlantic islands elevated long after volcanic activity ceased more than 30 million years ago.

5 per cent lighter than the adjacent mantle rock. This density differential generates sufficient buoyancy to maintain the Bermuda region between 1,300 and 2,000 feet higher than typical deep ocean floor.

Bermuda lies approximately 650 miles off the coast of North Carolina and is home to around 64,000 residents. The buoyant layer beneath it came into existence between 30 and 35 million years ago when molten rock from deep within the Earth ascended and spread beneath the crust before cooling and solidifying.

William Frazer and Jeffrey Park analysed more than two decades of natural earthquake vibrations captured by a single seismic monitoring station on Bermuda.

They tracked how fast-moving pressure waves transform into slower shear waves upon encountering boundaries between distinct rock layers. Through processing hundreds of seismic signals using specialised equipment and high-frequency filters, the team charted rock layers extending more than 25 miles beneath the surface. The findings were published in Geophysical Research Letters.

"Bermuda is an exciting place to study because a variety of its geologic features do not fit the model of a mantle plume," William Frazer said. " The discovery also sheds light on the Bermuda Rise, a vast underwater plateau spanning hundreds of miles. This elevated region has persisted for millions of years without any active volcanic or hot spot activity to sustain it.

The area exhibits a gravitational anomaly where Earth's pull registers slightly weaker than anticipated due to the lighter rock beneath. The reduced gravitational force causes the ocean surface to sit marginally higher over the Bermuda Rise, producing a geoid anomaly. The region displays pronounced magnetic irregularities that can affect compass readings and navigation instruments.

These magnetic disturbances stem entirely from iron and titanium-rich rocks remaining from ancient volcanic activity. GB News reported that for decades geologists had puzzled over how the popular holiday destination remained elevated above the deep ocean floor when similar islands typically require ongoing volcanic activity to remain above water.

The newly identified buoyant layer functions as an enormous geological flotation device.