Amino Acid Racemization, Biostratigraphy
Amino acid racemization biostratigraphy refers to using the ratio of right-handed (D) to left-handed (L) amino acids (D/L value) preserved in sediment or fossils to determine the age of sedimentary deposits including the duration of time recorded in sedimentary deposits. This can be done by direct comparison of D/L values to determine relative ages or by using calibrated D/L values to estimate ages in calendar years.
The age of sedimentary deposits is of fundamental importance to many topics in stratigraphy, sedimentology, evolutionary biology, and paleobiology. Amino acid racemization (AAR) provides a cost-effective way to directly date large numbers of fossils, and it has revolutionized the way paleontologists have been able to study the age of fossil deposits. AAR has made three key contributions to biostratigraphy. (1) AAR D/L values are one of many methods used to determine the relative age of sedimentary deposits (older deposits have higher D/L values)....
KeywordsSedimentary Deposit Coastal Sediment Fossil Assemblage Biostratigraphy Date Taphonomic Process
- Bowen, D. Q., Pillans, B., Sykes, G. A., Beu, A. G., Edwards, A. R., Kamp, P. J. J., and Hull, A. G., 1998. Amino acid geochronology of pleistocene marine sediments in the Wanganui basin; a New Zealand framework for correlation and dating. Journal of the Geological Society of London, 155, Part 3: 439-446.Google Scholar
- Hare, P. E., and Mitterer, R. M., 1967. Nonprotein amino acids in fossil shells. Yearbook Carnegie Institution of Washington, 65, 362–364.Google Scholar
- Kowalewski, M., Goodfriend, G. A., and Flessa, K. W., 1998. The high-resolution estimates of temporal mixing in shell beds: the evils and virtues of time averaging. Paleobiology, 24, 287–304.Google Scholar
- Martin, R. E., Wehmiller, J. F., Harris, M. S., and Liddell, W. D., 1996. Comparative taphonomy of bivalves and foraminifera from Holocene tidal flat sediments, Bahia La Choya, Sonora, Mexico (northern Gulf of California): taphonomic grades and temporal resolution. Paleobiology, 22, 80–90.Google Scholar
- Meldahl, K. H., Flessa, K. W., and Cutler, A. H., 1997. Time averaging and postmortem skeletal survival in benthic fossil assemblages: quantitative comparisons among Holocene environments. Paleobiology, 23, 207–229.Google Scholar