quinta-feira, 26 de julho de 2012
Meteorite crater discovered in Arctic
Keith Dewing, of the Geological Survey of Canada, stands on a meteorite crater’s edge on the northwest of Victoria Island, in Northwest Territories in July 2010, after researchers discovered evidence of the crater from helicopter. (CP)
Canadian researchers say they’ve discovered a 25-kilometre-wide meteorite crater in the western Arctic while they were updating maps.
University of Saskatchewan professor Brian Pratt and Keith Dewing of the Geological Survey of Canada made the discovery while exploring Victoria Island in a helicopter two years ago.
At the time, they were doing map work for a Natural Resources Canada energy and minerals program.
“It was one of the few parts of the Arctic that hasn’t been mapped in real detail. There was a map done in the 1960s but it was a very general map so we were going in to make it a more detailed map,” said Pratt.
“The chances of finding a new meteorite impact are a once-in-a-lifetime thing. So you can imagine that we were absolutely thrilled that we were the lucky ones.”
They say it took two years to properly confirm that it was a meteorite crater. They’ve produced a paper on the discovery that will now be open to peer review.
Pratt and Dewing say the crater is at least 130 million years old and could even be as old as 350 million years. They’ve named the new discovery the Prince Albert impact crater, after the name of the peninsula where it is located.
Pratt says it’s certainly a big crater, although it’s not the biggest.
According to the Geological Survey of Canada’s Earth Impact Database, operated by the University of New Brunswick, one of the largest meteorite craters in Canada is at Sudbury, Ont., at approximately 130 kilometres across. The database lists a crater in Chicxulub, Mexico, as one of the largest in the world at 150 kilometres across.
Beverly Elliott, data manager at the centre, says the Chicxulub crater is the one that’s thought to have wiped out the dinosaurs.
Elliott said the new crater on Victoria Island is still just a claim at this point as far as the centre is concerned. Peer review is still required before it gets on their list, she said, and it must also meet a certain number of other criteria.
“As soon as that publication comes out, we’ll have a look at it,” said Elliott, speaking from Fredericton.
There are at least 160 known meteorite features on Earth.
Publicado por Jorge M. Gonçalves às 10:03 da tarde