Chronology of British aggregates using amino acid racemization and degradation

Kirsty Penkman, Matthew Collins, David Keen, Richard Preece, 2011 (updated 2012)

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University of York
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Kirsty Penkman, Matthew Collins, David Keen, Richard Preece (2012) Chronology of British aggregates using amino acid racemization and degradation [data-set]. York: Archaeology Data Service [distributor]

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Image of Bithynia tentaculata

The project assessed the utility of a novel method of amino acid racemization analysis (Intracrystalline Protein Degradation, or IcPD, analysis of intracrystalline proteins) and interpretation on the calcitic opercula of the gastropod Bithynia.

The new technique of amino acid analysis developed combines a Reverse-Phase High Pressure Liquid Chromatography method (Kaufman and Manley 1998) with the isolation of an 'intra-crystalline' fraction of amino acids by bleach treatment (Sykes et al 1995). This combination of techniques results in the analysis of D/L values of multiple amino acids from the chemically protected organic matter within the biomineral, enabling both decreased sample sizes and increased reliability. This study has shown that the intra-crystalline fraction within calcitic fossils, such as the opercula of the freshwater prosobranch Bithynia, provides tighter clustering of amino acid data than obtainable from shells composed of aragonite (Penkman 2005).

The proposal tested the IcPD approach to date aggregate deposits. It is concluded that it is possible using this technique to provide relative age estimates of different aggregate deposits and furthermore to relate the age to the marine oxygen isotope record, so that it tis possible to link aggregates to specific phases of the Britsh Quaternary. The method has been used to provide a framework of age estimation beyond that which is possible using radiocarbon dating. The work has enabled the identification of the earliest human occupation in northern Europe (Pafitt et al 2005).

The final results of the project were published in Nature in 2011; doi:10.1038/nature10305


Kaufman D S, and Manley, W F, 1998 A new procedure for determining D/L amino acid ratios in fossils using Reverse Phase Liquid Chromatography, Quat Sci Rev, 17, p.987-1000

Parfitt, S.A., Barendregt, R.W., Breda, M., Candy, I., Collins, M.J., Coope, G.R., Durbidge, P., Field, M.H., Lee, J.R., Lister, A.M., Mutch, R., Penkman, K.E.H., Preece, R.C., Rose, J., Stringer, C.B., Symons, R., Whittaker, J.E., Wymer, J.J. and Stuart, A.J. 2005: The earliest humans in Northern Europe: artefacts from the Cromer Forest-bed Formation at Pakefield, Suffolk, UK, Nature 438, p.1008-1012.

Penkman, K.E.H. 2005: Amino acid geochronology: a closed system approach to test and refine the UK model. Unpublished PhD thesis, University of Newcastle.

Sykes, G A, Collins, M J, and Walton, D I, 1995 The significance of a geochemically isolated intracrystalline organic fraction within biominerals, Organic Geochem, 23 (11/12), p.1039-65