Brock university radiocarbon dating
Collagen was extracted from four macromammal bone samples of known-age (for details please refer to the Methods section) covering the full range of radiocarbon dating: a horse bone VIRI F (less than one C half-life), two whale bones VIRI I and VIRI H (approximately two half-lives) and a mammoth bone VIRI E (more than five half-lives).
The efficiency of eight collagen extraction protocols (in terms of quantity of protein extracted and collagen integrity) was tested on seven samples in a previous study currently used in our laboratory for the radiocarbon dating and isotopic analysis of macrovertebrate bone samples.
Here, we present the first radiocarbon dates obtained from minute amounts of bone (3–60 mg) using ECHo MICADAS, the compact AMS recently installed at Gif-sur-Yvette, France.
The optimization of our bone collagen extraction protocol allowed us to decrease the sample size by two orders of magnitude, while still extracting enough material (.
However, with decreasing sample sizes comes an increased risk of contamination from the burial environment and from laboratory handling.
Moreover, due to lower counting statistics, precision is usually much lower with the gas ion source than with the graphite target (2% vs.
The results obtained for the four known-age (VIRI) bone samples are summarized in Supplementary Table S1.
The impact of sample size on the collagen extraction yield and the radiocarbon age are discussed below. In this figure, a normalized yield was calculated for clarity and to enable direct comparisons.
They can be run in triplicates in order to improve the precision, but this requires the initial sample size to be increased, thus decreasing the interest of the gas ion source for archaeological samples.As the diagenetic alteration proceeds, the quantity and quality of the collagen decreases; consequently, the sample size must increase in order to compensate for protein loss.Radiocarbon dating ancient bones can therefore prove challenging.For well-preserved bone (20–25% collagen), the sample size decreases to about 10 mg.In practice, the manipulation of small bone samples presents several obstacles which are difficult to overcome, especially for ancient (Middle to Upper Paleolithic transition) samples.