Re: Early diets

rjy@uct.ac.za
Fri, 6 May 1994 16:34:08 GMT

In article <2qc0e3$l67@samba.oit.unc.edu> David.Bibb@launchpad.unc.edu (David Darryl Bibb) writes:

>What would the effect be on the radiocarbon dating of human material which
>came from someone who ate shellfish? Would the date be thrown off?

marine shellfish certainly would affect a radiocarbon date on the
bone collagen of the eater. There is an effect sometimes termed "the
apparent age of sea water" which requires that dates on shell be corrected
as they are too old. The amount to be subtracted varies regionally as one
can see if using the Calib. programme (Minze Stuiver et al)( and it will
also have cjanged with time). Eating the the flesh of molluscs will have an
effect roughly proportional to the amount of shellfood in the overall
protein diet. Excavators of shellmiddens should be aware of this if well
contextualised burials are obtained which appear to be slightly discrepant
in dated age compared to the horizons from which they came. FYI in S Africa
the subtracted time is €400 years.