These are also preserved in sediments which accumulated as a response to global climatic pulses, during the Pleistocene and beyond.
Therefore, amino acid geochronology has the potential to be widely applicable to the chronology of human evolution, as well as to the geological record.
Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world.
Since the development of accelerator mass spectrometry (AMS) for radiocarbon dating in the late 1970s, its ability to date small samples of bone has been of huge importance in archaeology and Quaternary paleoecology. can contain a heterogeneous mixture of non-collagenous molecules, including humic acids and other soil components that may be of a different age than the bone and therefore affect the accuracy of its 14C date.
This is achieved by chemical isolation of a fraction of proteins (intracrystalline) which behave as a closed system during diagenesis.
The extent of protein degradation within this closed system yields an estimate of the age since death of the organism.
This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea.Racemisation it is a post-mortem spontaneous reaction, involving the interconversion between two different forms of a single amino acid, the D- and L-forms (these are chemically identical but differ in the spatial configuration of their atoms). L-amino acids are present in living organisms, while D-amino acids are formed post-mortem by racemisation. This paper presents a novel method for the compound-specific 14C dating of individual amino acids, including hydroxyproline, from archaeological bone protein.It is based on a preparative, mixed-mode liquid chromatography separation of underivatized amino acids, entirely in aqueous solution and free of organic solvents.
The extent of racemisation can be measured by the ratio between the concentrations of D- and L-forms detected in a fossil sample: this is called D/L value.