[meteorite-list] Massive Asteroid Landed in Canada 70 Million Years Ago

[Ron Baalke]

http://www.ibtimes.co.uk/massive-meteorite-struck-canada-70-million-years-ago-killing-everything-1447588

Massive Meteorite Killed Everything after Striking Canada 70 Million Years Ago
By Hannah Osborne
International Business Times
May 7, 2014 

[Photo]
The crater in Alberta is about eight times as big as the Barringer Crater 
in Arizona.D. Roddy, U.S. Geological Survey

Canada experienced a massive meteorite strike some time in the last 70 
million years that killed everything in the near vicinity.

Published in the journal Meteoritics & Planetary Science, researchers 
discovered an ancient ring-like structure in southern Alberta that they 
believe to be the site of the strike.

They believe the meteorite strike was large enough to leave an eight kilometre-wide 
crater, and would have produced an explosion strong enough to destroy 
modern-day Calgary.

The site, dubbed the Bow City crater, was discovered in 2009 by geologist 
Paul Glombick, who noticed a bowl-shaped structure while logging data 
from the oil and gas industry. The Alberta Geological Survey then moved 
in to explore further.

Research leader Doug Schmitt said much of the evidence needed to work 
out the origin of the structure had been eroded away by time and glaciers.

[Map]
Map showing the structure and contour of the Bow City crater.Alberta Geographic 
Survey/University of Alberta

"We know that the impact occurred within the last 70 million years and 
in that time about 1.5km of sediment has been eroded," he said. "That 
makes it really hard to pin down and actually date the impact."

To work out where it came from, the team looked at seismic and geological 
evidence of the ring-like structure.

All that was left were the "roots" of the crater, which they established 
was probably 1.6 to 2.4kms deep when it first formed.

Graduate student Wei Xie said a meteorite strike big enough to make this 
crater would have had a devastating effect on anything living in the area: 
"An impact of this magnitude would kill everything for quite a distance. 
If it happened today, Calgary (200km to the northwest) would be completely 
fried and in Edmonton (500km northwest), every window would have been 
blown out.

"Something of that size, throwing that much debris in the air, potentially 
would have global consequences; there could have been ramifications for 
decades."