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From: ayers@convexs.UUCP
Newsgroups: net.sci
Subject: Re: Geology (Great Lakes) Question
Message-ID: <25500005@convexs>
Date: Wed, 14-Aug-85 11:34:00 EDT
Article-I.D.: convexs.25500005
Posted: Wed Aug 14 11:34:00 1985
Date-Received: Sun, 18-Aug-85 04:38:05 EDT
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Nf-From: convexs.UUCP!ayers    Aug 14 10:34:00 1985


/* ---------- "Geology (Great Lakes) Question" ---------- */
>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)?
>
>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)?

For the latest on plate tectonics, see the most recent issue of National 
Geographic...


> If you look at them (in particular, Superior, Michigan, and Huron),
> they are *very deep*.  For instance, Superior is 1300 feet deep.

>>Sorry, but most of the Great Lakes are *very shallow*.  It
>>is hard to find a place in Erie, Superior, and Huron more
>>than about 100 feet deep, and most of Michigan is less than
>>200 feet deep...

Time magazine, August 12, 1985, pg. 49:  "...on the first submarine 
exploration to the bottom of one of the world's biggest bodies of 
fresh water, Lake Superior...using the _Sea-Link_, they have been 
able to plunge right to the bottom.  The deepest point:  1,330 ft."


			Well, that's one mystery less...

				blues, II