For more than two decades, the Silverpit crater, a strange circular depression hidden under the North Sea, has baffled scientists. They wondered whether it was the scar of a massive asteroid strike or simply the result of ordinary geological shifts deep beneath the seabed.
Now, the mystery is finally solved. Using cutting-edge seismic imaging and microscopic analysis of rock samples, a team of researchers has found the strongest evidence yet that the Silverpit Crater, which is about three kilometers wide and buried under 700 meters of sediments, was created by an asteroid impact roughly 43 to 46 million years ago.
This is an important discovery as “we can use these findings to understand how asteroid impacts shaped our planet throughout history, as well as predict what could happen should we have an asteroid collision in the future,” Uisdean Nicholson, lead researcher and a professor of Geoscience at Heriot-Watt University, said.
The impact crater idea faced serious rejection
The Silverpit structure was first spotted in 2002 by petroleum geoscientists mapping the seabed, about 80 miles (128 km) off the coast of East Yorkshire. Its perfectly circular shape, central peak, and ring of faults looked suspiciously like an impact crater. However, many experts weren’t convinced by this idea.
So in 2009, a debate was conducted by the Geological Society of London to arrive at a decision. About 80 percent of the scientists voted in favor of the idea that the feature was caused by the movement of salt layers or the collapse of sediments.
“They had the big debate, and then they had a vote. It was overwhelmingly decided that it was a non-impact origin. Most people favoured the mundane explanation, and I think that reflects a tendency to reject the more spectacular explanation,” Nicholson added.
Therefore, for years, the impact crater idea seemed doomed. This changed when the Northern Endurance Partnership, a project exploring carbon storage beneath the North Sea, gathered new high-resolution seismic images of the seabed in 2022. This data provided much sharper views than earlier surveys.
Revisiting and validating the asteroid impact theory
When Nicholson and his team examined the 2022 data, they found unmistakable features of an impact in the form of sharply defined faults, troughs carved by water rushing back into the crater, and even pits outside the main rim that appeared to be secondary craters formed by debris flung outward.
Such secondary craters are rarely preserved on Earth, making Silverpit especially valuable.
However, the most decisive evidence came from rocks, not images. Back in 1985, British Gas had drilled a well just north of the crater and saved some of the sediments. Nicholson’s team analyzed grains from those samples and found something extraordinary.
Tiny quartz and feldspar crystals, no bigger than a human hair, that carried microscopic planar deformation features. These are atomic-scale scars caused by the immense pressures of an impact shockwave. No normal geological process could create them.
“These prove the impact crater hypothesis beyond doubt, because they have a fabric that can only be created by extreme shock pressures,” Nicholson said. Though the team only found one grain of quartz and one of feldspar showing these features, they were enough to tip the balance. “We were exceptionally lucky to find these, a real needle-in-a-haystack effort,” Nicholson added.
Eventually, by combining the seismic images, rock analysis, and computer models, the researchers confirmed that an asteroid about 160 meters (the size of the Great Pyramid of Giza) had slammed into the shallow sea more than 43 million years ago.
This impact triggered a tsunami up to 100 meters (328 feet) high, devastating the area and causing the creation of the Silverpit crater.
An interesting and rare finding
The confirmation of Silverpit as an impact crater adds a new member to Earth’s very short list of known impact scars that includes just about 200 on land and only 33 beneath the oceans.
Since the crater formed in water and was quickly buried by sediments, it has been preserved in remarkable detail, offering scientists a unique laboratory to study how impacts unfold in marine settings. That includes rare evidence of secondary craters, which could help researchers better understand how debris spreads during collisions.
The work also highlights how difficult it can be to prove an impact origin. For years, the lack of high-resolution data and physical evidence of shocked minerals made the Silverpit case controversial.
Even now, some skeptics may question the findings, since only a couple of shocked grains were discovered. The authors acknowledge this limitation, but they argue that the combination of geological, seismic, and microscopic evidence makes the impact explanation far stronger than any alternative.
Looking ahead, the researchers hope to use Silverpit to refine models of what happens when asteroids hit the sea. This information could prove vital if Earth faces a similar threat in the future.
The study is published in the journal Nature Communications.