A buried supervolcano off the east coast of England produced a massive eruption roughly 454 million years ago, according to a study published in the GSA Bulletin. Researchers from the British Geological Survey and the University of Oslo used zircon crystals extracted from boreholes in Lincolnshire and Norfolk to date the ancient event, solving a decades-old mystery regarding the origin of the Kinnekulle tephra ash layer spread across Northern Europe.
Dating the Ancient Supereruption via Zircon Crystals
Principal author Tim Pharaoh, a geophysicist at the British Geological Survey, stated that precise ages allowed the team to make bold assertions, calling the exact result extremely satisfying to uncover, according to the BBC. Researchers re-examined tiny zircon crystals about the width of a human hair that were pulled from boreholes 40 miles apart in Lincolnshire and Norfolk 80 years ago. These crystals form inside molten magma before an explosive event occurs.
Zircon contains trace amounts of radioactive uranium that decays into lead isotopes over time. By analyzing these isotopes, scientists determined the crystals formed approximately 454.4 million years ago—roughly 200 million years before dinosaurs walked the Earth. This timeline matches the age of the Kinnekulle tephra obtained in the Oslo Region during a previous study by University of Oslo researchers. Wind carried the ash from eastern England across the Tornquist Sea to settle on the seafloor of ancient Scandinavia.
The Scale of the Wash Igneous Complex
The eruption expelled tens to hundreds of cubic miles of Earth’s crust into the stratosphere with a force comparable to several thousand hydrogen bombs, based on researcher estimates. Despite this immense power, the volcano is completely hidden from surface view today. It lies buried deep underground, centered beneath the Wash estuary off England’s east coast, stretching beneath a flat landscape.
Did you know? Geophysical data indicates this ancient structure is not an isolated phenomenon. Scientists have identified it as part of a larger caldera system known as the Wash Igneous Complex, showing that multiple volcanic centers once dominated the regional subsurface.
While the complex is completely extinct and incapable of erupting today, its historic explosive capacity remains remarkable. Continued subsurface investigations in the region may reveal further details regarding England’s complex geological past.
Frequently Asked Questions
How did researchers discover the hidden supervolcano?
Researchers analyzed tiny zircon crystals extracted 80 years ago from boreholes in Lincolnshire and Norfolk, using uranium-lead isotope dating to determine their age.
How powerful was the ancient eruption?
According to the study’s authors, the eruption blasted hundreds of cubic kilometers of crust into the stratosphere with a force equivalent to thousands of hydrogen bombs.
Where is the supervolcano located?
The extinct supervolcano is centered beneath the Wash, an estuary off the east coast of England, forming part of the Wash Igneous Complex.
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