A massive asteroid slammed into the North Sea roughly 43 to 46 million years ago, triggering a tsunami more than 100 meters (330 feet) high. Now, after more than two decades of scientific disagreement, researchers have uncovered compelling evidence confirming the ancient collision.
The impact created what is now known as the Silverpit Crater, a massive structure buried deep beneath the seafloor. Although scientists first discovered it in 2002, its origins remained fiercely debated, with some researchers arguing that geological processes, rather than an object from space, were responsible.
A research team led by Dr. Uisdean Nicholson of Heriot-Watt University in Edinburgh has now provided the strongest evidence yet that Silverpit was formed by an asteroid or comet. By combining advanced seismic imaging, microscopic examination of rock samples, and computer simulations, the scientists have reconstructed the violent event and identified minerals that could only have formed under extraordinary pressure.
The findings, published in Nature Communications, establish Silverpit as one of the relatively few confirmed impact craters on Earth.
A Mysterious Crater Beneath the North Sea
The Silverpit Crater lies approximately 700 meters beneath the seabed in the southern North Sea, about 80 miles off the coast of Yorkshire, England. The crater itself measures roughly three kilometers across and is surrounded by a much larger, 20-kilometer-wide region of circular faults, which are fractures in the rock where movement has occurred.
When scientists first identified the formation in 2002, several features suggested that it had been created by a high-speed collision with an asteroid or comet.
Its nearly circular outline, elevated central peak, and surrounding rings of faults resembled structures found at other impact sites. Central peaks can develop when rocks compressed by a powerful collision rebound upward, somewhat like the way water rises in the center after an object splashes into a pool.
However, not everyone was convinced.
Some geologists proposed that the unusual formation resulted from the movement of underground salt deposits, which can deform the rock layers above them. Others suggested that volcanic activity had caused part of the seabed to collapse, producing a structure that only appeared to be an impact crater.
The disagreement persisted for years. In 2009, geologists even voted on the competing explanations, as documented in Geoscientist magazine. Most participants rejected the asteroid impact hypothesis.
The latest findings show that the impact explanation was correct.
Scientists Find the Smoking Gun for an Ancient Asteroid Impact
The breakthrough came from combining newly available seismic images with microscopic evidence recovered from beneath the seabed.
Seismic imaging allows geologists to investigate structures hidden underground by analyzing how sound waves travel through different layers of rock. This technique can reveal buried faults, craters, and other formations that cannot be observed directly.
Using the improved data, Nicholson and his colleagues were able to examine Silverpit’s internal structure in unprecedented detail.
But the most decisive evidence came from tiny mineral crystals discovered in rock cuttings collected from an oil well near the crater.
Dr. Uisdean Nicholson, a sedimentologist in Heriot-Watt University’s School of Energy, Geoscience, Infrastructure and Society, said: “New seismic imaging has given us an unprecedented look at the crater.
“Samples from an oil well in the area also revealed rare ‘shocked’ quartz and feldspar crystals at the same depth as the crater floor.
“We were exceptionally lucky to find these — a real ‘needle-in-a-haystack’ effort. These prove the impact crater hypothesis beyond doubt, because they have a fabric that can only be created by extreme shock pressures.”
Shocked minerals are particularly important because their internal crystal structures have been altered by immense pressure. Such changes can occur when an asteroid strikes at tremendous speed, generating powerful shock waves that pass through the surrounding rock.
Ordinary geological processes generally cannot produce these distinctive microscopic features. Their discovery at the same depth as the crater floor provides strong physical evidence that an extremely violent impact occurred.
A 160-Meter Asteroid Unleashed a Monster Tsunami
With the crater’s origins established, researchers used numerical models, or computer simulations based on physical laws, to reconstruct what happened during the collision.
Their results suggest that an asteroid approximately 160 meters across approached from the west and struck the seabed at a shallow angle.
Although much smaller than the asteroid associated with the extinction of the dinosaurs, an object of this size could still release an enormous amount of energy when traveling at cosmic speeds.
According to the simulations, the impact violently displaced vast quantities of rock and seawater, producing a towering curtain of debris before the material collapsed back into the ocean.
Dr. Nicholson said: “Our evidence shows that a 160-meter-wide asteroid hit the seabed at a low angle from the west.
“Within minutes, it created a 1.5-kilometer-high curtain of rock and water that then collapsed into the sea, creating a tsunami over 100 meters high.”
That means the collision sent material nearly a mile into the air before it fell back into the sea, generating a tsunami taller than a 30-story building.
Unlike ordinary wind-driven waves, tsunamis involve the movement of enormous volumes of water. They are typically generated when a sudden disturbance, such as an earthquake, underwater landslide, or asteroid impact, rapidly displaces the water above it.
The estimated height of Silverpit’s tsunami comes from computer modeling of the ancient impact rather than direct observation. Nevertheless, the reconstruction illustrates just how destructive even a relatively modest asteroid can be when it strikes the ocean.
A Scientific Debate Finally Settled After Decades
For Professor Gareth Collins of Imperial College London, the discovery brings a satisfying conclusion to a controversy he witnessed firsthand.
Collins participated in the 2009 debate over Silverpit’s origins and contributed the numerical simulations used in the new research.
Professor Collins said: “I always thought that the impact hypothesis was the simplest explanation and most consistent with the observations.
“It is very rewarding to have finally found the silver bullet. We can now get on with the exciting job of using the amazing new data to learn more about how impacts shape planets below the surface, which is really hard to do on other planets. “
The findings do more than settle an old argument. They also give scientists a valuable opportunity to study the underground damage caused by high-speed asteroid impacts.
Because much of Silverpit’s structure remains buried and well preserved, researchers can investigate how the collision fractured, displaced, and reshaped the surrounding geological layers.
These observations could help scientists interpret impact structures on other worlds, where the subsurface effects of collisions are often much more difficult to examine.
Why This Rare Asteroid Crater Matters
Earth has experienced countless asteroid and comet impacts throughout its history, but relatively few recognizable craters remain.
Weathering, erosion, sediment deposition, and plate tectonics continually reshape the planet’s surface. Over millions of years, these processes can wear down, bury, or completely destroy evidence of ancient collisions.
As a result, exceptionally preserved impact sites like Silverpit are scientifically valuable.
Dr. Nicholson said, “Silverpit is a rare and exceptionally preserved hypervelocity impact crater.
“These are rare because the Earth is such a dynamic planet — plate tectonics and erosion destroy almost all traces of most of these events.
“Around 200 confirmed impact craters exist on land, and only about 33 have been identified beneath the ocean.
“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 future.”
Hypervelocity impacts occur when objects strike at extremely high speeds, typically several kilometers per second. At those velocities, even an asteroid measuring only a few hundred meters across can deliver a devastating amount of energy.
With its origins now confirmed, Silverpit joins a small group of important underwater and buried impact structures, including the Chicxulub Crater in Mexico, associated with the mass extinction that wiped out the nonavian dinosaurs, and the Nadir Crater off the coast of West Africa, another recently confirmed asteroid impact site.
Together, these craters provide evidence of the powerful role cosmic collisions have played in shaping Earth’s geological and biological history.
By studying Silverpit’s remarkably preserved features, scientists hope to better understand what happens when an asteroid strikes the ocean, how the surrounding rock responds, and what such an event might mean for Earth in the future.
The research was funded by the Natural Environment Research Council (NERC).
