[meteorite-list] The Massive, Sudbury Impact Structure

From: Mark Fox <unclefireballmtf_at_meteoritecentral.com>
Date: Thu Apr 22 10:01:36 2004
Message-ID: <20020630195536.63425.qmail_at_web14909.mail.yahoo.com>

June 30, 2002

Greetings Meteorite Enthusiasts!

I have recently read about the famous Sudbury impact
structure, located in Ontario, Canada. It is the
second largest impact listed in the, "Rocks From
Space" crater list ---a gargantuan 155 miles wide!
It is also listed as being visible from the surface
and is commonly attributed to be roughly 1.87 billion
years old, making it the second oldest impact recorded
to date! Also astonishing is the fact that metallic
iron nickel grains have been found in some of the
impact breccias associated with the massive
devastation it caused. These grains are thought to
be pieces from the actual impactor! Amazing!

Thus, knowing this, some gnawing questions have come
up.

Firstly, where has the farthest piece of Sudbury
impact breccia been found? Could there be pieces
blown away as far as the Lower Peninsula of Michigan
or dragged there by glaciers?

Also, doesn't it seem rather odd for such a supposedly
ancient crater as the Sudbury Structure to be still
visible from the surface today? If it is indeed as
old as it has been assumed, then it would have had to
survive the erosion caused by the ancient shallow seas
that likely covered the area for many, many years.
Then of course, it would have had to likewise endure
the glaciers that probably swept over the area with
their demolishing movements. It seems hard to imagine
that such an impact structure could be as well
preserved as it sounds like today, including being
discernible from the ground.

Lastly, this brings up another question, one
concerning the iron-nickel grains. Wouldn't one
think that most of it should have rusted away during
the length of time that they are said to have been
here, including possibly being submerged in salt
water? I am mainly addressing the grains located near
the crater, at the earth's surface (that is, if there
are any found there).

Please correct me if I'm wrong with any of the above
statements!

Long strewn fields!

Mark Fox
Newaygo, MI USA

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Received on Sun 30 Jun 2002 03:55:36 PM PDT