“Study: Dinosaurs Wiped Out by Twin Meteor Strikes - AOL News” |
| Study: Dinosaurs Wiped Out by Twin Meteor Strikes - AOL News Posted: 30 Aug 2010 04:42 PM PDT (Aug. 30) -- It took not one but two major meteor strikes to wipe out the dinosaurs about 65 millions years ago, a new study has concluded, with about 2,000 years passing between the two events. The Gulf of Mexico meteorite strike, which left a huge crater known as the Chicxulub, has for years been seen as the single event that brought a complete end to the planet's dinosaur population. But new evidence has shown that a meteorite came thundering down on Ukraine before that, devastating most parts of present-day Eastern Europe and Russia and most of the dinosaurs roaming that part of the world. In between, the study suggests, it seems the Earth was bombarded for about 2,000 years by an almost continuous meteorite shower. Many of them probably landed in the sea, making the evidence hard to find, but the researchers believe those that hit the Earth contributed to the dinosaurs' disappearance.  Lennart Preiss, AFP / Getty Images A new evidence indicates that meteorite strikes 2,000 years apart were responsible for the dinosaurs' extinction. "It seems very unlikely that those two major events were the only two that occurred," the leader of the research team, professor David Jolley of Aberdeen University, told AOL News. "The Ukrainian crater is about 20 miles wide; the one at the Gulf of Mexico is much bigger, certainly one of the largest meteorites ever to hit the Earth," Jolley said. "But it's highly unlikely that these were the only two; in fact we're pretty certain." The Boltysh Crater in Ukraine was first reported in 2002, but until the current study, published in the journal Geology, scientists did not have evidence of whether or how it was related to Chicxulub. Jolley and his team, working for the Geological Society of America, dug deep into the crater and examined pollen and spores of fossil plants buried in the mud. They found that about 2,000 to 5,000 years after the Ukraine meteorite impact, all the vegetation had grown back. "The Ukraine meteor's impact extended about 500 miles," Jolley said. "There was a big flash, a big shock wave, with everything covered in ash." The clincher of its relevance, however, came when it became evident that the renewed vegetation was wiped out again about 2,000 years later, and there could really be only one explanation. "The Gulf of Mexico impact was so big it destroyed all the vegetation from the Gulf to Eastern Europe and, of course, across the American Midwest," Jolley said. And what are the chances that another huge meteorite might hit Earth again? "Well, the records show that we're not likely to see anything like a major meteorite impact for a long, long time," Jolley told AOL News, although he conceded with a chuckle to a highly anxious reporter that, "Why not now? It's just by chance." Professor Simon Kelley of the U.K.'s Open University, co-author of the study, told the BBC that a second layer of fern spores found at Boltysh just over a yard over the first layer was interpreted as "the aftermath of the Chicxulub impact" and that the two meteorites struck thousands of years apart. "It's quite possible that in the future we will find evidence for more impact events," Kelley said. Professor Monica Grady, a meteorite expert at the Open University who did not take part in the recent study, was quoted by The Daily Telegraph as saying that the meteor shower could have been caused by "the collision of Near Earth Objects." This entry passed through the Full-Text RSS service — if this is your content and you're reading it on someone else's site, please read our FAQ page at fivefilters.org/content-only/faq.php This posting includes an audio/video/photo media file: Download Now |
| You are subscribed to email updates from Add Images to any RSS Feed To stop receiving these emails, you may unsubscribe now. | Email delivery powered by Google |
| Google Inc., 20 West Kinzie, Chicago IL USA 60610 | |
0 comments:
Post a Comment