[meteorite-list] Forest Fire Leads to Discovery of Sudbury Impactite

Sterling K. Webb sterling_k_webb at sbcglobal.net
Sun Jul 15 23:33:21 EDT 2007


Hi,

    Forgive me for being less sensational than the AP.
This story had been in the news before, so I guess
the real news is that the AP saw fit to make it a story.
Always glad to have a meteorite make the news, even
if it takes almost two billion years to do it.

Sterling K. Webb
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http://www.space.com/news/070715_ap_minn_meteorite.html

Forest Fire Leads to Ancient Meteorite Discovery 
By Associated Press -- 15 July 2007; 08:25 pm ET


GRAND MARAIS, Minn. (AP) -- A forest fire has led 
to a chance discovery of debris from the impact of a 
meteorite 1.85 billion years ago, more than 450 miles 
away at Sudbury, Ontario.

Geologists had scheduled a field trip in May along the 
Gunflint Trail in northeastern Minnesota, but most areas
 they wanted to explore were closed because of a wildfire 
that charred more than 118 square miles.

Geologist Mark Jirsa of the Minnesota Geological Survey 
went up the trail to scout new locations and, in a spot he 
had never visited before, stumbled across debris now 
linked to the Sudbury impact.

That impact created a crater more than 150 miles across, 
scattering rock and dust over nearly a million square miles.

"It's fairly dark rock,'' Jirsa said. "They look like concrete,
 but in this concrete you would throw pieces of rock of 
all sizes and shapes and in all possible orientations.''

Previously, material thrown out by the impact had been 
found as far from Sudbury as Hibbing, about 125 miles 
farther to the southwest from Grand Marais. However, 
the tiny fragments at Hibbing were found in core samples 
from 800 to 1,000 feet below the surface, while the rock 
layer containing larger chunks at the Gunflint site lies exposed.

"I think the excitement for the people of Minnesota is that 
we are one place in the world where you can see evidence 
of an ancient meteorite impact,'' said University of Minnesota 
geology professor emeritus Paul Weiblen, who is studying 
the debris. "This is the second-oldest and second-largest 
impact crater in the world.'' 



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