Hello Jens,
Regarding your chalk fossils -- there are two possible causes I can think of:
If they were collected from the coast and then they will be impregnated with salt from the seawater, over time this will crystallise and force the specimen apart. It can be prevented by soaking the specimen as soon as it has been collected for several months in freshwater changing the water from time to time. But once the problem of crystallisation shows itself it is probably too late to do anything about it, except perhaps take up the study of microfossils!
The other possibility is that it is pyrite within the specimen that is decaying.
Best wishes, Mike.
Please note - This document was created using voice recognition software. There may be some unusual or amusing errors in it because of this.
Mike Horne,
Department of Chemistry,
University of Hull.
01482 465466 ('phone and fax)
On Mon, 23 Jan 2006 09:47:17 +0000 Jens Lehmann
<[log in to unmask]> wrote:
> Dear colleagues,
> we face the problem that some of our fossils from the British Chalk (in
> particular those from the Santonian of Kent) start to decay - only about 10
> years after collecting and although the material has been varnished after
> preparation. I guess this should be a familiar problem for some institutions
> in the UK. Are there any suggestions why the decay starts and how to stop it?
> Many thanks,
> Jens
>
> ----------------------------------------------------------------------------------
> Dr. Jens Lehmann
> Geosciences Collection of the University of Bremen
> - Head -
> University of Bremen - Faculty 5 (Geosciences)
> Klagenfurter Strasse
> 28359 Bremen
> Germany
> Tel.: ++49-(0)421-218-2520
> Fax ++49-(0)421-218-7480
> [log in to unmask]
> http://www.geosammlung.uni-bremen.de/
----------------------------------------
Michael J Horne
Email: [log in to unmask]
University of Hull
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