Mystery of Silverpit Crater Solved After 20 Years: It Was Left by an Asteroid
An asteroid that fell into the North Sea caused a giant tsunami – scientists have obtained final proof.
For more than two decades, geologists debated the origin of a mysterious crater on the North Sea floor. A new study has ended the discussion and demonstrated the scale of the catastrophe that occurred tens of millions of years ago.
An international team of scientists has confirmed that the mysterious Silverpit crater on the North Sea floor was formed by the impact of an asteroid or comet approximately 43–46 million years ago. This is reported by Sciencedaily.
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What helped confirm the cosmic origin of the crater?
The work was led by Dr. Uisdean Nicholson from Heriot-Watt University in Edinburgh. The research was funded by the UK Natural Environment Research Council.
The Silverpit crater lies about 700 meters below the seabed in the southern North Sea, approximately 130 kilometers from the coast of Yorkshire.
It was discovered back in 2002, but since then geologists have debated its origin. Some believed the structure was formed by the impact of a cosmic body, while others explained it by the movement of underground salt layers or volcanic processes. The debate was so intense that in 2009 geologists even held an official vote on the crater's origin. At that time, the majority of participants did not support the asteroid impact hypothesis.
New data have completely changed this picture.
What evidence was found?
The researchers used modern seismic tomography, which provides detailed three-dimensional images of geological structures beneath the Earth's surface. The method works on a principle similar to medical ultrasound, using the reflection of sound waves.
The new data allowed a detailed study of the crater's internal structure. In addition, scientists examined rock samples obtained from drilling an oil well near Silverpit. It was there that they discovered so-called "shocked" crystals of quartz and feldspar.
"The new seismic survey gave us an unprecedented detailed view of the crater. Samples from the oil well also contained rare 'shocked' quartz and feldspar crystals at the same depth as the crater floor," explained Dr. Uisdean Nicholson.
According to him, finding such minerals was incredibly lucky.
"We were incredibly lucky to find them – it was a real 'needle in a haystack.' They unequivocally confirm the impact crater hypothesis, because such a crystal structure can only arise under extremely high impact pressure," the researcher noted. Such minerals are considered one of the most reliable pieces of evidence for asteroid impacts, as similar structures cannot form through ordinary geological processes.
What was the force of the impact?
According to computer modeling, an asteroid about 160 meters in diameter struck the North Sea.
It flew from the west at a shallow angle to the surface. During the impact, almost instantly a huge column of rock debris and water about 1.5 kilometers high formed. When it collapsed back into the sea, a tsunami over 100 meters high arose.
Although this asteroid was significantly smaller than the celestial body that formed the Chicxulub crater about 66 million years ago and is associated with the mass extinction of dinosaurs, its energy was enough for large-scale destruction. The crater itself Silverpit has a diameter of about three kilometers. Around it also extends a system of ring-shaped geological faults about 20 kilometers in diameter.
Why are such craters so rare?
According to the researchers, the Earth is constantly changing under the influence of erosion, tectonic processes, volcanism, and other geological phenomena. Because of this, most traces of ancient collisions with cosmic bodies gradually disappear.
Dr. Nicholson notes that to date, scientists have confirmed the existence of about 200 impact craters on land and only about 33 under the seabed.
"Silverpit is a rare and exceptionally well-preserved impact crater. Such objects are not common because the Earth is a very dynamic planet. Plate tectonics and erosion destroy almost all traces of such events," he explained. Scientists believe that the new results will help better understand how asteroid impacts influenced the Earth's development in the past, as well as improve models for predicting the consequences of possible future collisions.
Professor Gareth Collins from Imperial College London, who created computer models for the study, admitted that he had always considered the asteroid impact hypothesis the most convincing.
"I always thought that the impact hypothesis was the simplest and best aligned with observations. It is very gratifying that we finally found decisive proof. Now we can use this unique data to better understand how cosmic impacts shape planets beneath their surface," the scientist concluded.
