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

See allHide authors and affiliations

Science  25 Mar 1977:
Vol. 195, Issue 4284, pp. 1333-1335
DOI: 10.1126/science.195.4284.1333


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.

Stay Connected to Science