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FW: Leaned something new! RE: Some Data ....



 <980128.72605.qm@web52605.mail.re2.yahoo.com>
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Thank you Michelle. You explained it nicely. I didn't think I had to
go into detail on this one. Everyone who has ever been in the field has
experienced this at one time or another. You do have to professionally
stabilize these artifacts any way you are able to before excavation to
an institute. --dale=20
----------------------------------------
> Date: Sun=2C 1 Nov 2009 11:38:04 -0800
> From: drakeducaine@yahoo.com
> To: villandra@austin.rr.com=3B dinosaur@usc.edu
> Subject: Re: Leaned something new! RE: Some Data ....
>
> Because not all fossils are bone hard=2C dry=2C or 'rockicized'=2C even i=
f they date back that far. A good deal of Hell Creek material is preserved =
in matrix containing a lot of clay=2C which swells when wet and shrinks whe=
n dry. As clay seeps into fractures=2C pores=2C joints=2C etc. this leads t=
o increased fracturing of those bones=2C especially when weathering brings =
them closer to the surface. This results in a lot of Hell Creek fossils tha=
t look nice on the surface=2C but the cancellous or spongey part of the bon=
e underneath that is literally a mineralogical house of cards. Applying con=
solidant SLOWLY helps to fill in microscopic fractures=2C fill pore spaces=
=2C and shore up the inner structure of the fossil. It's not easy to do in =
the field=2C especially if you're working with damp matrix. It's time consu=
ming=2C but totally worth it when the specimens get to the laboratory prep.=
 stage. Hosing the specimen down quickly with the same consolidant can wash=
 it away like a
> sandcastle at high tide.
>
> The term 'preservative' reminds me of the ones used in food. Consolidants=
 don't prevent chemical breakdown of fossil material=2C and can even speed =
it in some instances if it sets off chemical reactions. They provide struct=
ural support more than anything else.
>
> Michelle Pinsdorf
> South Dakota School of Mines and Technology
>
> --- On Sun=2C 11/1/09=2C Dora Smith wrote:
>
>> From: Dora Smith=20
>> Subject: Re: Leaned something new! RE: Some Data ....
>> To: wdm1949@hotmail.com=2C "DML"=20
>> Date: Sunday=2C November 1=2C 2009=2C 10:15 AM
>> Someone fill in this amateur.
>>
>> You've got a 70 million plus year old bone hard=2C dry=2C
>> rockicized fossil.
>>
>> Why on earth would you add a preservative?
>>
>> Yours=2C
>> Dora Smith
>> Austin=2C TX
>> tiggernut24@yahoo.com
>>
>> ----- Original Message ----- From: "dale mcinnes"=20
>> To: "DML"=20
>> Sent: Sunday=2C November 01=2C 2009 10:37 AM
>> Subject: FW: Leaned something new! RE: Some Data ....
>>
>>
>>>
>>> <1257024771.4aecad03dc4f1@webmail.chariot.com.au>
>>> Content-Type: text/plain=3B charset=3D"iso-8859-1"
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>>>
>>>
>>> As a side note here=3D2C even perfectly formed undamaged
>> fossils
>>> can on occasion turn instantly soggy by simply adding
>> a preservative
>>> whilest in the field. You can instantly turn fossils
>> into mush by
>>> doing so. It would appear that if they are laced with
>> 1000s of tiny microsc=3D
>>> opic fractures and you add a liquid=3D2C they will flow.
>> One has=3D20
>>> to add preservatives one drop at a time=3D2C allowing
>> each drop to harden
>>> before applying the next application. I believe this
>> is the reason most
>>> fossils are destroyed when amateurs attempt to recover
>> them. --dale=3D20
>>>
>>> ----------------------------------------
>>>> Date: Sun=3D2C 1 Nov 2009 08:32:51 +1100
>>>> From: dannj@alphalink.com.au
>>>> To: dinosaur@usc.edu
>>>> Subject: Re: Leaned something new! RE: Some Data
>> ....
>>>>
>>>> On Sat=3D2C Oct 31st=3D2C 2009 at 4:58 AM=3D2C B tH=3D20
>>>> wrote:
>>>>
>>>>> I never have heard that fossils could be in
>> such
>>>>> a condition. I have seen some rocks that were
>> easily
>>>>> crunched up by hand - must be along the same
>> lines.
>>>>> When things like this occur=3D2C is it due to
>> something that
>>>>> has happened to the fossil "recently" - how
>> could it
>>>>> have survived up till now in such a state?
>>>>
>>>> I suspect most 'oatmeal' fossils are due to
>> chemical changes that have
>>>> occured while they were in the upper soil layers.
>> They were probably
>>>> much harder for most of their fossil 'life'=3D2C
>> otherwise you'd think that
>>>> pressure put on them at any decent depth would
>> squish them beyond
>>>> recognision. Keep in mind that even solid and
>> apparently hard bone can
>>>> gradually 'flow' under immense pressures=3D2C
>> resulting in distortion of th=3D
>>> e
>>>> fossil.
>>>>
>>>> --
>>>>
>> _____________________________________________________________
>>>>
>>>> Dann Pigdon
>>>> GIS / Archaeologist Australian Dinosaurs
>>>> Melbourne=3D2C Australia http://home.alphalink.com.au/~dannj
>>>>
>> _____________________________________________________________
>>>> =3D20
>>>
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>
>
>                                        =20
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