Electron spin resonance dating (Esr)

Abstract

Due to methodological advances, which significantly increase the accuracy of ESR dating of Pleistocene and Holocene corals, ESR dating has become an efficient tool in earth sciences for geochronological studies on coral reef terraces in the past decade. ESR dating of Holocene corals coincides with the variability of14C ages caused by the marine reservoir effect, but without any doubt TIMS Useries dating of Holocene coral is more precise, much faster, and much cheaper than ESR dating. ESR dating of Pleistocene corals permits us to differentiate between the main marine isotope stages (MIS) 5, 7, 9, 11, and 13 as well as between the substages 5e-2,3 and 5e-1, 5c, and 5a-2 and 5a-1. The average error is about 5–8%. Late Pleistocene corals can be dated with a similar accuracy as with the TIMS U-series method in this time range, although the individual errors of ages are significantly larger than those of U-series data. The advantage of ESR, however, is that the upper dating limit for corals is probably above 500,000 years. If weathering and recrys-tallization from primary aragonite to calcite of the coral material could be excluded, dating of coral with an age of several million years should be feasible from the physical point of view. All in all, future research in ESR dating corals should be focused on (a) a more precise identification of diagenetic transformations of the primary aragonitic fabric of the coral samples and (b) on the creation of a single-aliquot dating technique that uses orientated aragonitic polycrystals.