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From: eugene@ames.UUCP (Eugene Miya)
Newsgroups: net.sci
Subject: Re: Geology (Great Lakes) Question
Message-ID: <1072@ames.UUCP>
Date: Thu, 8-Aug-85 04:53:49 EDT
Article-I.D.: ames.1072
Posted: Thu Aug  8 04:53:49 1985
Date-Received: Sun, 11-Aug-85 06:23:52 EDT
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Organization: NASA-Ames Research Center, Mtn. View, CA
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> Does anybody out there know about the origin of the Great Lakes
> (and have any newer theories come out lately, particularly
> with regards to plate tectonics and hot spots)?
> 
> Michigan and Huron do the same (but not by as much).  How did glaciers
> manage to dig these lakes so deep?????  Other glacial lakes
> (Manitoba, Great Slave) are relatively shallow.
> 
> I'm wondering if some plate tectonics might be involved here.  The only
> other inland areas below sea level I can think of had tectonic causes
> (Death Valley, Dead Sea, Caspian Sea, Loch Ness).  Might the Great Lakes
> be the remnant of a failed rifting (which was much later covered by ice)?

First, I should say that I an not a geologist by training, but have
worked with glaciologists.  DO NOT UNDER-ESTIMATE the powers of frozen
water!  New theories in this area are not necessarily better.

I don't think tectonic activity is greatly involved in the case of the
Great Lakes.  You would see relatively recent evidence of this, however,
let me point you to the latest issue of Time Mag.  Research is taking
place in Superior which will shed more light on it's formation. Patience!

--eugene miya
  NASA Ames Research Center
  {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene
  emiya@ames-vmsb