Isoleucine Epimerization for Dating Marine Sediments: Importance of Analyzing Monospecific Foraminiferal Samples

The rate of isoleucine epimerization in fossil planktonic foraminifera is strongly species-dependent. Alloisoleucine/isoleucine ratios of two species of the same age can vary by more than a factor of 2. This finding, in combination with the known temporal and spatial variability of foraminiferal ass...

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Bibliographic Details
Published in:Science
Main Authors: King, Kenneth, Neville, Colleen
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 1977
Subjects:
Online Access:http://dx.doi.org/10.1126/science.195.4284.1333
https://www.science.org/doi/pdf/10.1126/science.195.4284.1333
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Summary:The rate of isoleucine epimerization in fossil planktonic foraminifera is strongly species-dependent. Alloisoleucine/isoleucine ratios of two species of the same age can vary by more than a factor of 2. This finding, in combination with the known temporal and spatial variability of foraminiferal assemblages, demonstrates the critical importance of basing geochronological studies of marine sediments on monospecific samples. One rapidly epimerizing species generates a calibration curve of potentially high precision for dating sediments between the ages of about 50,000 to 400,000 years.