This crater is noteworthy because it is contemporary with the crater that struck the Yucatan southeast of the pyramids of Teotihuacan and the period when the dinosaurs went extinct. Ancient magnetic north was in the North Sea where the 60-million-year-old crater was discovered. GIANT CRATER FOUND UNDERSEA By Irene Brown, Discovery News Aug. 1 — A quest for oil in the North Sea has turned up an ancient impact crater so well preserved that it could give scientists fresh insight into the effects of large meteorite impacts on Earth. The 12-mile wide crater is buried under 120 feet of water and more than 900 feet of sediment, which has helped preserve features that on Earth's surface would have been eroded away. The planetary scar is believed to have been caused by a meteor or comet impact 60 million to 65 million years ago, and is unlike anything that has been found on Earth or the moon. In fact, it is so pristine that it resembles craters previously found only on Jupiter's icy moons. The find was announced in this week's edition of the journal Nature, which reports that the crater "may be the best three-dimensionally imaged impact structure on Earth." British geophysicist Phil Allen stumbled upon the so-called Silverpit crater while studying three-dimensional seismic data for a petroleum client. The crater has a cone-shaped peak at its center, which typically is found only in much larger craters, and is surrounded by a series of concentric rings. The ring pattern resembles features found in large craters on Callisto and Europa, two of the icy moons of Jupiter. Allen didn't realize what he was looking at until a chance visit by a colleague, geologist Simon Stewart, who years earlier had predicted that the new 3D maps being developed for oil and gas exploration would one day uncover an impact basin. "I'm a general structural geologist and look at all kinds of stuff," said Stewart, adding that he has not spent much time focusing on impact craters. Most small meteor craters are a simple smooth bowl-shape, such as the Baringer Crater in Arizona, said John Spray, a geologist at the University of New Brunswick. As the diameter of the crater increases, so does its complexity, with central peak structures, peaked rings and multiple rings found in craters 155 miles or more in diameter. "We know so little about how impact structures are created when meteorites and comets hit, any new example helps," said Spray. The North Sea crater, which the scientists named Silverpit after a nearby sea-floor channel, is shaped like a basin with at least 10 distinctive concentric rings located between about one to six miles from the crater center. The main crater is about 1.5 miles wide, with a central peak that is believed to have formed when Earth rebounded from the impact of the incoming meteor or comet. "It's puzzling," said Spray. "Normally, you'd expect a crater to be about 200 kilometers (124 miles) in diameter before you have these features. This challenges our accepted thought and dogma." Scientists hope to obtain drill-cutting samples from Silverpit for additional studies, such as mineral deformations from shock effects. "My guess is that there are many of these craters out there but we haven't been seeing them because they're buried," said Spray. "With new technology, we're starting to see new things." The meteor that formed the Silverpit crater hit Earth within roughly the same time period as the asteroid or meteor that is tied to the demise of the dinosaurs. That impact gouged a 93-mile wide crater in Mexico's Yucatan Peninsula. *3D pic* Copyright © 2002 Discovery Communications Inc.