Bermuda is a fascinating puzzle in the world of geology. While it’s famously linked to the mysterious Bermuda Triangle, it’s the islands themselves that intrigue scientists. They sit atop a thick layer of Earth’s crust, raising questions about how they exist here at all.
Recently, two seismologists, William Frazer from Carnegie Science and Jeffrey Park from Yale University, explored this mystery. The Bermuda archipelago, which consists of 181 islands, is believed to have formed about 33 million years ago from volcanic activity. Typically, volcanic island chains, like Hawaii, have a history of active volcanoes and a deep-rooted mantle plume beneath them. This mantle plume generally causes the seafloor to swell, forming the islands we see today.
However, Bermuda poses a unique challenge. There’s no sign of volcanic activity for millions of years, yet the land remains above the ocean. Without the expected mantle plume, researchers were puzzled about why the islands haven’t sunk into the sea.
To solve this, Frazer and Park analyzed seismic data, looking at how earthquake waves traveled through the Earth’s mantle beneath Bermuda. They discovered a thick layer of low-density rock about 20 kilometers (12 miles) down. This layer is acting similarly to a mantle plume, helping to elevate the crust and support the islands.
This ‘underplating,’ as they call it, might be what keeps Bermuda above water. The researchers noted, “This thick layer beneath the crust likely was formed when Bermuda was volcanically active and could support the bathymetric swell.”
Interestingly, this discovery sheds light not just on Bermuda but also contributes to our understanding of similar geological formations worldwide. According to a recent study by the US Geological Survey, areas with similar geological features can give insight into volcanic activity and its relationship with sea-level rise. Places like Bermuda, which have no recent volcanic activity, can help scientists predict changes as sea levels rise due to climate change.
As sea levels continue to rise, the preservation of these islands will become even more critical. Current projections indicate that global sea levels could rise by 1 to 2 feet by 2050, significantly impacting coastal areas, including Bermuda. So, while the islands may stand firm for now, ongoing research and data are essential for understanding their future.
For those interested in the science behind it, this research was published in Geophysical Research Letters, highlighting the significant findings that could change how we view volcanic islands.
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