ESR DATING OF QUATERNARY CORALS FROM BARBADOS - IMPLICATIONS FOR SEA-LEVEL RECONSTRUCTION

The systematic ESR dating of fossil corals was first applied in the 1980s. Since this time, this relatively new dating technique has been improved substantially and ESR dating results now convincingly matched those from the well-established techniques of C-14 and TIMS U-series dating (Radtke et al. 2002; Schellmann et al. 2002). ESR dating of coral sampled from Barbados allows for differentiation between the marine isotopic substages 5e, 5c, and 5a. However, by dating older samples it is only possible to distinguish between the main marine isotopic stages 9, 11, and 13, and 15, most likely due to recrystallization effects. More than 300 new age determinations presented here suggest that, during the last 400 ka, sea level has oscillated more strongly than previously thought. For example, several sub-stages with sea-level between 10 m and 25 m below present sea level are preserved on south Barbados from the last two Interglacial sea-level highstands (5a-1, 5a-2, 5c-1, 5c-2, 5c-3, 7-1). The sea-level fall at the end of the relatively short last and penultimate interglacial transgression maximum (5e-3 and 7-3) is documented by individual reef terraces (5e-1, 5e-2, 7-2, 7-3). Our study enables a revised estimate of the spatial and temporal variation in tectonic uplift rate within west and south Barbados. These new rates are an essential requirement for more precise glacio-eustatic sea-level reconstructions during the Late and Middle Pleistocene from this region. Our findings also provide strong evidence for non-linear crustal uplift during the late Quaternary - an assumption which has been pivotal to most previous studies in the region.

References: U. Radtke, G. Schellmann, A. Scheffers, K. Kelletat and Kromer, B. (2003) ESR and C-14 dating of corals deposited by Holocene tsunami events on Curacao (Netherland Antilles) (Quat. Sc. Rev., in press). G. Schellmann, U. Radtke, E.-K. Potter, T.M. Esat, M.T. McCulloch and K. Lambeck (2002) Comparing ESR and TIMS U/Th age measurements of oxygen isotope stage 5c and 5a corals from Barbados (10th Intern. Conf. on Luminescence and ESR Dating, Reno, June 24-28, 2002; Abstr., 156)