I agree with David, you will either get a good date, ensured by quality control measures on the extracted collagen, or you will fail to get a date. You don't say what the nature of the environment was. If the bone is friable then it may well have lost its collagen, but it is also possible under acidic, waterlogged conditions to lose the mineral and retain a lot of collagen. In an acidic aerobic environment, where mineral is lost first, followed by collagen, first I'd advise going for the densest bones available for the best chance of collagen preservation.
If you have the facilities, a quick test is to take a small amount of bone, weigh it, dissolve in 1M HCl in a test-tube, filter, dry and weigh the resulting insoluble residue which is likely to be mostly collagen. If you get more than 1% of the initial weight it is well worth trying a C14 date.
Best wishes
Andrew
--
Dr. Andrew Millard [log in to unmask]
Durham University
Senior Lecturer in Archaeology Tel: +44 191 334 1147
Archaeology: http://www.dur.ac.uk/archaeology/
Personal webpage: http://www.dur.ac.uk/a.r.millard/
> -----Original Message-----
> From: David Orton [mailto:[log in to unmask]]
> Sent: 01 December 2011 17:33
> Subject: Re: Radiocarbon dating
>
> Hi Martyn,
>
> In my experience it's surprisingly hard to judge collagen
> preservation
> from the visual condition of bone, although there's certainly a
> correlation. As I understand it poor preservation shouldn't have
> any
> impact on the reliability of the results, but might simply result
> in
> insufficient material to date, in which case you could potentially
> waste
> a lot of money (Oxford charge half price for failed samples, I
> believe,
> so that'd be in the region of £150). If you don't want to risk
> that,
> it's possible to test for collagen preservation in advance, for a
> much
> smaller sum (think ~£5) - I spent hours drilling powder samples for
> Alex
> Bayliss one summer for that purpose! Unfortunately I don't have any
> details of the labs providing that service, but could chase it up
> if
> you're interested.
>
> Best,
> David
>
> > Dear Zooarch
> >
> > My query concerns the suitability of samples for radiocarbon
> dating. I am currently analysing a pig skeleton excavated from
> Somerset which the excavators would like to carbon date as there
> are no associated artefacts. However, despite being exposed in the
> grave as an intact specimen, the skeleton is very poorly preserved
> and has severely fragmented since its removal from the context due
> to the soil environment in which it lay. The skull is missing so
> there are no teeth, but there are a couple of specimens - distal
> humerus, the glenoid of a scapula, lumbar bodies - which remain
> intact enough to provide samples. So my question is, will these
> still provide suitable samples for dating since they are so badly
> preserved? Does the degradation of the bone reduce the ability for
> carbon dating for providing a reliable result or will these
> specimens be 'ok'?
> >
> > All thoughts are welcome.
> >
> > Cheers,
> > Martyn Allen
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