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Re: north by nortwest



At 1:07 -0500 7/12/98, Allan Edels wrote:

>    I believe that BOTH expansion and shrinkage would occur.  I think that
>ice, while it is generally more compact than water, has a point (4 degrees
>below the freezing point of water - I think the measurement is in Farenheit
>not Celsius degrees) where it expands.

Water is at its most dense at 4 deg C (and I think that's one reason why
refrigerators work best at that temperature).  I don't know about ice's
density curve, but you may be confusing this number.  In any case, ice is
always less dense than liquid water - that's why it floats.

>This would push the pieces of the
>fossil apart (due to the ice that would have gotten into most of the
>fractures in the fossil), then some shrinkage would occur as the ice melted
>away.  Finally, when you are left with just water and fossil, you have a
>very waterlogged fossil, and need to work very hard to preserve the fossil.
>(You might end up with thick fossil stew - the consistency of cold oatmeal).

Wouldn't this depend on the degree of permineralization?  I mean, if the
thing is a rock (of insoluble minerals), essentially, the only damage to
the thing will have already occurred when the ice crystals expanded in the
first place.  The rock may fall apart in chunks, but it could be glued
together - lots of rocks survive deep freeze.

>    Sherry - you might want to check with Kelly Gittis - she worked on a
>frozen, waterlogged mammoth in Newfoundland (or Nova Scotia).  She would
>probably know the exact sequence of events and what methods were tried to
>speed up the removal.  (The fossil did not have hair or skin attached, as
>far as I remember).

>From the number of rescued frozen mammoth/wooly rhino carcasses floating
around, I suspect it's not a difficult process.  Speak Russian?


Laurie Nyveen                                  lawrence@dsuper.net
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Editor, Netsurfer Digest - <http://www.netsurf.com/nsd/index.html>
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