Radiocarbon dating bone
Possible contamination of samples can also occur in temperate zones.
While low collagen content is a condition we cannot overcome, we can use several chemical and elemental indicators in order to assess collagen quality.
Diagenetic changes in bone are liable to cause erroneous radiocarbon dates on bone because of the mixing of sample and environment C atoms they can bring about.
Likewise, radiocarbon dating can provide information on the extent of such mixing.
In a combustion and graphitization setup like that installed at INFN-LABEC, Florence, measurement can be easily performed using an elemental analyzer when combusting the sample prior to graphitization, thus requiring no extra effort (or extra amount of sample) during the preparation procedure.If Beta Analytic did not perform the chemical pretreatments and/or extractions, the lab cannot specifically testify as to the material that was dated because certain steps affecting the sample quality have been outside of its control and scope of its accreditation.The lab highly recommends NOT to send powdered bones.The content and the quality of collagen can vary significantly, mainly depending on bone preservation and diagenesis.
Generally speaking, environmental conditions such as low p H level of soils, high temperatures, and percolating groundwaters, typical of arid and tropical zones, can affect the preservation of collagen; at the same time, bones recovered in such environments are more likely to be contaminated with carbon from the surrounding environment.The processes involved which may mix chemically, physically, or biologically the C atoms of the sample are outlined, and the methods used in practice to reverse this mixing are described.