For 23 years, the Silverpit Crater, a 3.2-kilometer-wide depression beneath the North Sea, about 130 kilometers off the coast of Yorkshire, sat in geological limbo. Discovered in 2002 by petroleum geoscientists Simon Stewart and Philip Allen, who proposed an impact origin in Nature, the structure was met with skepticism. In 2009, the Geological Society of London formally voted against the impact hypothesis, favoring salt withdrawal as the explanation. The question appeared closed.
Now, a team led by Uisdean Nicholson at Heriot-Watt University has delivered the proof that ends the debate: two microscopic grains of shocked quartz and feldspar, recovered from rock cuttings drilled by British Gas in 1985 and stored for four decades.
The study, published in Nature Communications in September 2025 and circulated more widely this June, confirms that a rocky asteroid approximately 160 meters wide, roughly the size of a football stadium, struck the shallow Eocene sea at an angle from the west-northwest, traveling at 15 kilometers per second. The impact created a transient crater three kilometers wide and one kilometer deep in approximately 12 seconds, and sent a tsunami more than 100 meters (330 feet) high racing across the prehistoric North Sea basin.
The smoking gun
The key evidence came from the 43/25-1 oil well, drilled by British Gas in 1985, whose cuttings had been sitting in storage for 40 years. Nicholson’s team identified two shocked grains at precisely the stratigraphic level of the crater floor: one quartz grain at 463 meters depth and one potassium feldspar grain at 494 meters.
The quartz grain contains two sets of planar deformation features indexed as {10-13} and {10-14}, microscopic fracture patterns that form only under extreme shock pressures of approximately 10 to 13 gigapascals. The feldspar grain shows parallel amorphous lamellae decorated with fluid inclusions, also diagnostic of hypervelocity impact. Both are invisible to the naked eye and required painstaking petrographic analysis.
“This was a needle-in-a-haystack effort,” Nicholson said.
New high-resolution three-dimensional seismic data revealed the crater’s full internal structure: a central uplift, an annular moat, a damage zone approximately 18 kilometers across, secondary craters, and resurge scarps, features consistent with a marine impact. Biostratigraphy using nannofossils from 31 samples constrained the impact to the middle Eocene, between 43 and 46 million years ago.
Numerical impact simulations by Gareth Collins at Imperial College London replicated the observed crater morphology using a 160-meter rocky asteroid (dunite, density 3,300 kilograms per cubic meter) striking a shallow sea at 15 kilometers per second.
Why the debate lasted two decades
The original 2002 proposal was plausible but circumstantial, seismic imaging showed a circular structure consistent with impact, but the gold-standard evidence, shocked minerals, had never been found. Alternative explanations, salt withdrawal deforming overlying sediments, or volcanic collapse, could not be ruled out without petrographic shock evidence. The 2009 Geological Society vote reflected this evidentiary gap. Nicholson’s paper notes that the vote and the subsequent lack of new data “appears to have led many researchers to consider the question closed, with limited further research” in the subsequent 15 years.
What the impact means
At 160 meters, the Silverpit asteroid was substantially larger than the 50-meter object that exploded over Tunguska in 1908, but still an order of magnitude smaller than the 10-to-15-kilometer Chicxulub impactor that ended the Cretaceous. Impacts of Silverpit’s scale are estimated to occur roughly once every 700,000 years.
Only approximately 33 confirmed submarine impact craters are known on Earth, compared to roughly 200 on land. Silverpit is now among the best-preserved submarine examples, offering a rare window into how marine impacts differ from terrestrial ones, particularly in tsunami generation and crater preservation under sediment cover.
Source: Nicholson U, de Jonge-Anderson I, Gillespie A, et al. Hypervelocity impact origin of the Silverpit Crater, North Sea. Nature Communications. 2025;16:8312. doi:10.1038/s41467-025-63985-z