Mon, 22 Dec 2008 19:17 UTC
Rather than just one space rock hitting the ground, as first thought, the bounty appears to consist of thousands of meteorite fragments, according to the team that has co-ordinated the recovery.
The group, organized by the University of Calgary, has recovered more than 100 meteorites from the site southwest of Lloydminster, on the border of Alberta and Saskatchewan, and says many more are still out there.
Volunteer searcher Ellen Milley, who is pursuing her master's at the University of Calgary's geoscience department, found the first meteorite fragments on Nov. 27.
U of C planetary scientist Alan Hildebrand said in a written statement there are roughly 2,000 meteorites of 10 grams or more, per square kilometre, in the northern part of the field where the fragments were found.
Altogether, he calculated, there are likely more than 10,000 meteorites on the ground in the area.
"The last day that the search teams were out, it snowed all day and we still found five meteorites which is ridiculous. It shows just how many are out there," Hildebrand said.
The area where the meteorites were discovered is being called Buzzard Coulee, after a valley near the hamlet of Lone Rock, Sask., where Milley found the first fragments.
The largest meteor fall previously on record occurred when hundreds of fragments were recovered near Bruderheim, Alta. in 1960.
Hildebrand said the November event could easily surpass those numbers.
"I think that the number of individual meteorites that will be recovered for Buzzard Coulee will easily set the Canadian record for the largest fall recovery, but we still don't know how big the biggest meteorite out there is, so we don't know how much mass we can expect to be recovered of the approximately 1 tonne that fell," Hildebrand said.
A large-scale search will be held in the spring, prior to the start of cultivation and seeding, to recover as many meteorites as possible, Hildebrand said.
He said the initiative planned for spring will be "the biggest meteorite search effort that Canada has ever seen."
Scientists are still examining the fragments in an attempt to learn more about where the meteor came from. It has already been classified as an H4 type.
The rock is on the low end of the H4 scale, meaning it didn't experience high heat on its parent asteroid.
"The meteorite also appears to show that different types of material are mixed together in a subtle way, but we will have to study more thin sections to better understand this," said Dr. Melinda Hutson, a Canadian scientist at Cascadia Meteorite Laboratory at Portlant State University who helped classify the meteorite.
"The meteorite is slightly shocked, so the material was possibly stirred by an impact on its parent asteroid."