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Re: north by nortwest



Laurie, etc.:

    My understanding is that there is an additional expansion point of ice -
where it is less compact than usual.  The 4 degree figure is indeed for the
densest water (sorry).  I'm not sure where that point would be.

    The recovery of mammoths and wooly rhinos from the permafrost of the
Russian/Siberian steppes is not exactly the same as recovering older
fossils - which would have a higher degree of permineralization.  I agree
that the degree of permineralization seems to be important in this
particular discussion - if not fully permineralized, the fossil would be
more subject to the stresses we've been talking about.  (Lots of glue
needed).  BTW, I have a translation of a 1912(?) paper on mammoths and wooly
rhinos.

    My discussion of the waterlogged fossil (i.e. the oatmeal consistency
fossil stew) is based on a presentation by Kelly Gittis - some of the bones
that she and her group recovered from the mammoth site actually ended up as
that pasty concoction.  They had to setup climate/humidity-controlled
holding racks for the remainder of the fossils.  The humidity was modified
over the months to slowly bring the fossils back to 'normal'.

    Allan Edels



-----Original Message-----
From: L Nyveen <lawrence@dsuper.net>
To: Edels@email.msn.com <Edels@email.msn.com>; dinosaur@usc.edu
<dinosaur@usc.edu>
Date: Monday, December 07, 1998 6:35 AM
Subject: 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
>__________________________________________________________________
>Editor, Netsurfer Digest - <http://www.netsurf.com/nsd/index.html>
>DNRC Minister of Adding "ue" to Words That End in "log"
>"All we are, basically, are monkeys with car keys."
>                             - Grandma Woody (Northern Exposure)
>
>