“Gigantic” in its size and quality of discovery. Structure may explain why the Bermuda Islands appear to float above the surrounding ocean.
The North Atlantic’s latest mystery lies beneath the enigmatic Bermuda Triangle.
In a recent study in Geophysical Research Lettersresearchers revealed a strange 20 kilometer layer of rock beneath the oceanic crust under the Bermuda Islands.
As geologists point out, a level of thickness like this has never been observed in any other similar layer around the world.
“Normally, we have the bottom of the oceanic crust and, after that, we would expect the mantle to be there. However, in Bermuda there is this other layer that is implanted under the crust, within the tectonic plate on which they rest”, explained the lead author of the study, William Frazerseismologist at Carnegie Science, in Washington DC, at .
Although the origin of this layer is not entirely clear, it could explain a persistent mystery about Bermuda, Frazer added.
A special and mysterious region
The Bermuda Islands sit on an oceanic rise, where the oceanic crust is higher than the surrounding areas. But there is no evidence of ongoing volcanic activity creating this elevation — the island’s last known volcanic eruption occurred 31 million years ago.
The discovery of the new giant structure suggests that the last eruption may have injected mantle rock into the crustwhere it solidified in place, creating something similar to a raft that raises the ocean floor by about 500 meters.
Bermuda has long had a reputation for mystery, particularly as to why Bermuda’s ocean rise exists. Island chains like Hawaii are thought to exist due to mantle hot spots, which are places in the mantle where hot material rises, creating volcanic activity.
As Live Science details, the new study used records from a seismic station in Bermuda of large, distant earthquakes that have occurred around the world to obtain an image of the Earth up to about 50 kilometers below Bermuda. He examined places where the seismic waves from these earthquakes suddenly changed. This revealed the unusually thick rock layer, which is less dense than the surrounding rock.
“There is still this material left over from times of active volcanism under Bermuda and which is potentially helping to keep them high like this area of great relief in the Atlantic Ocean,” he told Live Science Sarah Mazzaa geologist at Smith College in Massachusetts, who was not part of the study.
Frazer’s team is examining other islands around the world to determine whether there are layers similar to the one found beneath Bermuda, or whether the archipelago is truly unique.
