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)....
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