Skip to main content
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1973 May;70(5):1331–1334. doi: 10.1073/pnas.70.5.1331

Racemization Reaction of Aspartic Acid and Its Use in Dating Fossil Bones

Jeffrey L Bada *,*, Reiner Protsch
PMCID: PMC433490  PMID: 16592082

Abstract

In the time interval datable by radiocarbon, and at the temperatures of most archeological sites, a substantial amount of racemization of aspartic acid takes place. By determination of the amount of racemization of aspartic acid in bones from a particular location which have been dated by the radiocarbon technique, it is possible to calculate the in situ first-order rate constant for interconversion of the L- and D enantiomers of aspartic acid. Once this “calibration” has been calculated, the reaction can be used to date other bones from the deposit that are either too old to be dated by radiocarbon or that are too small for radiocarbon dating. The only assumption required with this approach is that the average temperature experienced by the “calibration” sample is representative of the average temperature experienced by older samples. This “calibration” technique is used herein to date bones from the Olduvai Gorge area in Tanzania, Africa.

Keywords: Olduvai Gorge; 5,000-70,000-years-old range; hominids

Full text

PDF
1331

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bada J. L., Luyendyk B. P., Maynard J. B. Marine sediments: dating by the racemization of amino acids. Science. 1970 Nov 13;170(3959):730–732. doi: 10.1126/science.170.3959.730. [DOI] [PubMed] [Google Scholar]
  2. Emiliani C. The last interglacial: paleotemperatures and chronology. Science. 1971 Feb 12;171(3971):571–573. doi: 10.1126/science.171.3971.571. [DOI] [PubMed] [Google Scholar]
  3. Leakey L. S., Protsch R., Berger R. Age of bed v, olduvai gorge, Tanzania. Science. 1968 Nov 1;162(3853):559–560. doi: 10.1126/science.162.3853.559. [DOI] [PubMed] [Google Scholar]
  4. Manning J. M., Moore S. Determination of D- and L-amino acids by ion exchange chromatography as L-D and L-L dipeptides. J Biol Chem. 1968 Nov 10;243(21):5591–5597. [PubMed] [Google Scholar]
  5. Rechnitz G. A. Lead poisoning in children: detection by ion-selective electrode. Science. 1969 Oct 24;166(3904):532–532. doi: 10.1126/science.166.3904.532-a. [DOI] [PubMed] [Google Scholar]
  6. Wehmiller J., Hare P. E. Racemization of amino acids in marine sediments. Science. 1971 Sep 3;173(4000):907–911. doi: 10.1126/science.173.4000.907. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES