Carbon dating question: Can traditional radio carbon techniques be used to date mammal skeletal samples in the 500-200 years BP range? We occasionally recover bison skeletal remains from a wetland area on the National Elk Refuge (NER)in Jackson Hole, Wyoming. Bison were extirpated from NER from approximately 1840-1975, and these remains clearly pre-date 1975. I would like to establish the age of these specimens. Any help would be appreciated.
Dear Eric,
Definitely carbon dating will help to establish the accurate age-range that you have mentioned, provided you have taken care of the alteration effect of bones. The following work will give you better idea about the dating methods and their limitations:
Grün, R. (2006). Direct dating of human fossils. American journal of physical anthropology, 131(S43), 2-48.
You have to take into account that carbon-14 has a half-life of approx. 5700 years. So dating in that comparibly small time-frame will not be all too accurate.
IMHO, I'd say that, if you have the resources to do it, you should give C14 a try. I would go with AMS, naturally (smaller sample demands, quite accurate results under good preservation conditions of the organic matter/absence of contamination).
Nevertheless, you must bear in mind that you may end up with a margin of error sufficiently large to render your interpretation inconclusive regarding your desired outcome - given the rather narrow timeframe you're dealing with.
Also, I'm thinking of the context where those remains were found... Were there ANY associated signs of material culture, that might serve as preliminary chronological indicator?
BTW, Eric, it just crossed my mind that humic acids (present in wetlands) may also be a source of contamination that will deviate C14 results.
One other element to take into consideration while deciding on your course of action.
Thank you all for your thoughtful responses. The margin of error associated with the estimates in my main concern, but I will likely do some pilot sampling and give it a try. Regarding the humic acid issue, our wetland is a calcareous fen with typical PH in the 8-9 range. I will have to explore the ramifications of C14 testing under these environmental conditions. Once again, thanks!
Glad to be of help, Eric! Regarding the soil composition, I'm not an expert, but you might ask the lab where you plan to send the samples to be dated on some more details regarding that. Usually they are willing to help out with that sort of issues.
If it's not a problem, could you please share the results (even if in a non-detailed manner) once you get them? You got me really curious, given that this is an uncommon situation.
All best!
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