Le Manitoba est en train de devenir un paradis terrestre de météorites (désolé article en anglais seulement).
Record year for meteorite recovery in Canada
University of Calgary
Dec. 15, 2005
Manitoba becomes meteorite capital as Canada's most successful meteorite
hunter proves meteorite "dumping ground" theory east of Winnipeg.
The discovery of four new meteorites in 2005 makes it a record-setting
year for recovering rocks from outer space in Canada and also confirms a
University of Calgary scientist's belief that an extraordinary
concentration of meteorites left behind after the last Ice Age is
located in southeastern Manitoba.
"Scientists have been collecting meteorites in Antarctica for more than
two decades where glaciers have concentrated them along the edges of the
continent. Many have postulated that the continental ice sheet that
covered Canada might also have done this," said U of C planetary
scientist Dr. Alan Hildebrand, co-director of the Prairie Meteorite
Search. "That another meteorite was found with relatively little effort
pretty much establishes that an unusual concentration of meteorites does
exist in eastern Manitoba, and the continental glaciers are the obvious
culprit to have put them there."
After becoming the first Canadian to discover two separate meteorites
last summer, Winnipeg-based rock collector Derek Erstelle has now
shattered the Canadian record by locating fragments of weathered iron
that the Prairie Meteorite Search has shown to be another new meteorite
from the bush near the Ontario border.
The discovery is exciting news for Manitoba's astronomy community.
"We're obviously very excited about these meteorite discoveries, and we
hope that this signals even more discoveries in the future," said Scott
Young, manager of the Manitoba Museum's planetarium and science gallery.
"Manitoba is under-represented in the meteorite game, so this is our
chance to climb the meteorite ladder."
Erstelle's latest find happened in October while he was testing
Hildebrand's theory that his previous two meteorites were found
relatively close together in the forest because the rocks dropped there
when the glaciers that covered much of North America were retreating
about 12,000 years ago. The third meteorite is a collection of
heavily-rusted iron fragments that were found about 40 kilometres from
Erstelle's previous two discoveries north of the town of Pinawa.
"I try to mimic animal behaviour when I'm hunting," Erstelle said of his
effective meteorite hunting technique.
"For meteorite searching I sit up high like a raptor and scan the
exposed gravel banks with binoculars for unusual rusty spots. Then I
check each one to see if something unusual is there."
He found the newest specimen on a gravel bar of the Whiteshell River
just above where it empties into Lone Island Lake in the Whiteshell
Provincial Park, about 100 km east of Winnipeg. The Lone Island Lake
meteorite is the 8th meteorite to be discovered in Manitoba, the 9th
meteorite identified by the Prairie Meteorite Search, and the 68th new
meteorite to be recovered in Canada.
Erstelle was able to recover about five kilograms of material after
locating the crumbling remains of the meteorite with his metal detector.
"The rusty meteorite was already breaking to pieces, but was triggering
my metal detector. I dug to get additional pieces and eventually
screened the gravel around where the pieces were to get all that I
could," he said.
Hildebrand, holder of a Canada Research Chair in Planetary Sciences,
said he was initially skeptical Erstelle had found another meteorite.
"Derek's recent discovery is very weathered, so much so, that when I
received the samples that I didn't think that they were meteorites,"
Hildebrand said. "But I couldn't tell what type of rock they were so I
cut one, and to my surprise found metal inside. We checked it with the
microprobe and the metal contained nickel confirming its origin."
In July, the Prairie Meteorite Search confirmed that two fragments of a
meteorite Erstelle found about 40 kilometres away near Bernic Lake in
2002 were from a separate meteorite than a similar-looking specimen he
collected near Pinawa in 1998 or 1999. Hildebrand determined that the
rocks were found where two lobes of the ancient Laurentide ice sheet met
about 11,500 years ago, providing an explanation for their remarkably
close proximity. Hildebrand said further tests will be done to determine
how long the rocks have been on Earth and to see if more meteorites can
be found in the area.
"If these meteorites fell on the ice sheet, they would have to have been
on Earth for 12,000 years or longer," Hildebrand said, noting that
Erstelle's latest find is very weathered, indicating that it fell to
Earth long ago. "We now have to make a plan for the Prairie Meteorite
Search to further investigate the region next summer and I expect
Manitoba could well become Canada's pre-eminent meteorite province
Young is also hopeful more meteorites will be found in Manitoba next year.
"I encourage people to keep an eye out for unusual looking rocks, and
bring them to someone who can identify them - the meteorites are out
there somewhere, just waiting to be found," he said.
The Prairie Meteorite Search is led by Hildebrand, Dr. Peter Brown from
the University of Western Ontario and Dr. Martin Beech from Campion
College at the University of Regina. They are all members of the
Meteorites and Impacts Advisory Committee (MIAC) to the Canadian Space
Agency. MIAC is Canada's volunteer group charged with the investigation
of fireballs and the recovery of meteorites. The Canadian Space Agency
funded most of the project's field costs for the summer of 2005.
Media event and interview opportunities in Winnipeg:
A news conference will be held in the planetarium of the Manitoba Museum
on Thursday, Dec. 15, beginning at 10 am. Dr. Alan Hildebrand will give
a brief presentation on meteorite research and the "dumping ground"
theory, followed by one-on-one interview opportunities with Hildebrand,
Derek Erstelle and Scott Young.
The Manitoba Museum is located at 190 Rupert Ave. in Winnipeg.
A map with driving directions is located at:www.manitobamuseum.ca/gi_find.html
Additional information about the Prairie Meteorite Search is available
on the project's website: www.geo.ucalgary.ca/PMSearch/
Media Relations Advisor - Research
University of Calgary
Phone: (403) 220-7722
Cell: (403) 651-2515