Accessibility statement

Improving the reliability of amino acid geochronology

Description

The importance of a robust chronology for Quaternary sediments cannot be underestimated.

In recent years advances have been made in Amino Acid Racemization (AAR; Penkman, 2005), combining the isolation of an 'intra-crystalline' fraction of amino acids by exhaustive bleach treatment of ground shell carbonate (Sykes et al., 1995) with a new Reverse-Phase High Pressure Liquid Chromatography (RP-HPLC) method (Kaufman & Manley, 1998).

This combination of techniques results in the analysis of D/L values of multiple amino acids from the chemically-protected protein within the biomineral, enabling both decreased sample sizes and increased reliability. The intra-crystalline protein occurs within a 'closed system' during the burial history of the shell, vital for the application of this technique for geochronological purposes. Amino acid data obtained from the intra-crystalline fraction of calcitic biominerals indicate this to be a particularly robust repository for the original protein, with this coherent system maintained as far back as the Pliocene.

Details

Project members
Project dates
  • 2005-2008
Funding bodies

Objectives


We aim to develop amino-acid racemization (AAR) as a dating tool by:

  • using laboratory methods and computational chemistry to:
    • establish a closed chemical system
    • test non-linear models of decomposition kinetics
    • develop methods of internal validation based on other amino acids
  • testing the method on Pleistocene molluscs

Projects

  • 2006-2009 Amino acid racemization in calcite: Dating the Pleistocene. Wellcome
  • 2005-2006 Amino acids in corals; range finders for sclerochronology and markers of bleaching? NERC
  • 2004-2005 chronology of British Aggregates. English Heritage/ALSF
  • 2004-2005 How useful is amino acid racemization as a tool for geochronology? A test of natural variability in Quaternary sediments. NERC
  • 2000-2004 Dating the Thames Terraces: Amino acid racemisation comes in from the cold. NERC
  • 2001 - on going High resolution Geochronological and Seasonal Dating of Marine Molluscs from Archaeological Deposits