Amino Acid Racemization Dating

Kirsty Penkman*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter


Amino acid racemization (AAR) chronology depends on the time-dependent breakdown of proteins (and their amino acid building blocks) in fossils. It covers the time-range from ~20years ago to at least 3Ma and, therefore, is applicable over the whole Quaternary Period and into the late Pliocene. As this is a particularly challenging time period for quantitative age dating, amino acid geochronology can provide valuable insights into how deposits correlate with each other, ultimately enabling links to be made between individual sites and the global climate signal. Developed in the 1960s, the application of this technique has helped shape current understanding of interglacial and glacial events over Pleistocene timescales, providing a useful tool beyond the limit of radiocarbon dating. Over the last 30years, a deeper appreciation of the complexities, limitations, and strengths of amino acid geochronology has resulted in a number of methodological developments. Separation of a range of amino acid chiral pairs through new gas and liquid chromatography methods, as well as isolation of intra-crystalline protein from fossil biominerals, have both enabled identification of compromised systems and provided greater confidence in amino acid dating results. Extension of the method to different biominerals (e.g. mollusk shell, eggshell, corals, foraminifera, ostracods and tooth enamel) has enabled the technique to be applied across a wide range of environments.

Original languageEnglish
Title of host publicationEncyclopedia of Geology
Subtitle of host publicationVolume 1-6
Number of pages12
ISBN (Electronic)9780081029091
Publication statusPublished - 1 Jan 2020

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd. All rights reserved.


  • Amino acid
  • Amino acid racemization (AAR)
  • Aminostratigraphy
  • Epimerization
  • Geochronology
  • Intra-crystalline protein decomposition (IcPD)
  • Paleothermometry
  • Pleistocene
  • Quaternary

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