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Re: freeing fossils from matrix
> Date: Sat, 17 Sep 1994 10:17:03 -0400
> Reply-to: Lightwaves@aol.com
> From: Lightwaves@aol.com
> To: Multiple recipients of list
<dinosaur@lepomis.psych.upenn.edu>
> Subject: freeing fossils from matrix
> Does anyone out there know a safe way to release fossils from the
limestone
> matrix holding them?
> I have tried hydrocloric and acetic acid, but in both cases the fossils
> dissolve as well as the limestone, and that's very frustrating.
These
> fossils are from the deposits in north Arkansas, and the limestone
is extra
> hard. Most attempts at chipping the rock away results in explosive
> fracturing.
> There are several nice specimens, but they're locked up 'til I can
figure
> out a way to free them.
>
> Tahnx :-)
> Roger A. Stephenson (lightwaves)
> Morrilton, AR 72110
> 501-354-6439
>
>
I agree that the best answer is to use mechanical means. I don't
know the material, but I have dealt with some bones in nodules that
cannot be prepped using acid. If the matrix is softer than the bone I
would go for air abbrasive techniques although you sometimes lose
the outermost thin layer of bone if it is not done carefully. I have
used this technique on phosphatised Carboniferous shrimps, and
have been able to prepare individual blood vessels. Hot/cold preps
are sometimes damaging as well. I have used freeze/thaw on some
Silurian fish nodules which does seem to work. On larger boney
material I would be afraid of cracking through the bone. I guess it is
just trial and error. Experiment on some less crucial material first.
Neil Clark
Curator of Palaeontology
Hunterian Museum
University of Glasgow
email: NCLARK@museum.gla.ac.uk
The first law of Geology is the law of supposition.
(Geological Howlers - ed. WDI Rolfe)